AN-1456_Micrium_RTOS..
Contents
1. x N app_probe c 380 40 xi M includes h 0 D zi AB os_cfah 0 Oe a AB probe_com_cfa h 0 0 zi AB vectors c 256 O xf 3 EQ BSP 1K ge ex MD bsp c 482 2 n AB bsp h 0 0 zi AB Keypad c 76 0 ex AB keypad h 0 Oe a AB nemo 387 0 exi AB nem h 0 0 zi AB sevenSegment c 303 5 exi E sevenSegment h 0 D zi M sevenSegDisp_0S c 69 20 mi AB sevenSegment s 32 0e x Eq uC CPU 8 0 exi AB cpuh 0 0 zi AB cpuas 8 O mi AB cpu_def h 0 Oe a HE3 uC LIB 1K 0e exi AB lib_str c 1223 0 x AB lib_str h 0 Oe a AB lib_def h 0 0 zi AB lib_mem c 466 O x E lib_mem h 0 0 zi 3 amp 3 uCALCD 840 108 xi 36305 66 2 ex 3 amp 3 uC 05 II 66 20 mi AB Icd_os c 66 2 nm 14 Micripm uC OS II uC LCD and uC Probe for the Freescale MC9S12DG256 Eq Source 774 106 xi AB lede 774 106 xi AB lcdh 0 0 zi uC 0S ll 13K Ke exi 2 3 Port 222 20 of ED os_cpu_as 113 0e ex AB os_cpu_c c 109 2 exi M 05 CPU h 0 o x Source 12K Ke ex E os_core c 2942 3713 xi AB os_dbg_r c 113 0e ex AB os_flag c 1581 0 e exi AB os_mbox c 830 0 exi AB os_mem e 554 0e xf AB os_mutex c 1263 0 exi AB os_g c 1284 oe ex AB os_sem c 762 oe exi AB os_time c 374 0e ex AB os_task c 1813 oe ex AB os_tmr c 1616 0 e exi AB ucos_i h 0 0 zi 4 uC Probe 2K 926 e xi amp g2. 0 2 0 DispClrLine 1 5 OSFlagPost keypadEnFlagGrp 0x01 OS FLAG SET amp err 6 while err OS_NO_ERR 7 OSTimeDlyHMSM 0 0 1 0 OSFlagPost keypadEnFlagGrp 0x01 OS FLAG SET amp err DispClrLine 0 8 for i 0 i lt 3 i 2 DispStr 0 0 KeypadEnStr OSTimeDlyHMSM 0 0 0 500 DispClrLine 0 OSTimeDlyHMSM 0 0 0 500 19 L2 3 1 L2 3 2 L2 3 3 L2 3 4 L2 3 5 L2 3 6 Micripm uC OS II pC LCD and pC Probe for the Freescale MC9S12DG256 aboutStrPtr aboutStr for i 15 i gt 0 i 10 if aboutStrPtr 0 DispStr 0 i aboutStrPtr OSTimeDlyHMSM 0 0 0 100 while aboutStr sizeof aboutStr aboutStrPtr gt 16 11 for DispStr 0 0 aboutStrPtr t OSTimeDlyHMSM 0 0 0 100 i 15 i gt 0 i 12 if aboutStrPtr 0 DispStr 0 0 aboutStrPtr DispChar 0 i OSTimeDlyHMSM 0 0 0 100 DispClrLine 1 OSFlagPost keypadEnFlagGrp 0x01 OS_FLAG_CLR amp err 13 while err OS_NO_ERR 14 OSTimeDlyHMSM 0 0 1 0 OSFlagPost keypadEnFlagGrp 0x01 OS_FLAG_CLR amp err DispClrScr 15 for i 0 i lt 3 i 16 DispStr 0 0 KeypadDisStr OSTimeDlyHMSM 0 0 0 500 DispClrLine 0 OSTimeDlyHMSM 0 0 0 500 Define constant strings that will be displayed on the LCD Strings declared with the const keywo
3. EVB Once the application has been initialized the on chip PLL is configured to 48MHz which results in a 24MHz bus clock The PLL settings may be changed from within bsp h Refer to the section labeled Configuring the PLL for more information Next p Cc OS Il requires the use of an ECT channel for periodic time keeping This application configures ECT channel 7 for the pC OS II Ticker however if TC7 is not available you may configure an alternate ECT timer channel by adjusting the macro named os TICK OC within bsp h accordingly If the ECT channel is changed then the file vectors c will also require modification See the section labeled vectors c for more information Lastly all ISRs must be written as specified within the section labeled Creating Interrupt Service Routines Creating ISRs from C without the proper pC OS II primitives will cause task scheduling jitter which could result in poor real time performance for some applications Micripm pC OS Il uC LCD and pC Probe for the Freescale MC9S12DG256 1 05 uC Probe uC Probe is a Microsoft Windows program that displays the content of system variables on various user definable graphical elements such as simulated mechanical counters graphs on screen LEDs and so on In order for piC Probe to display information about your application an ELF file must be generated by the user s compiler The ELF file contains the names and addresses of all the global s
4. app e lt gt a 5 if uC_PROBE_OS_PLUGIN gt 0 uC PROBE COM MODULE gt 0 HCS12 Serial Monitor clima y B E extern void AppProbeInit void endif Files Link Order Targets Debug e Fie Code Data za Ga Sources 2K BK mi AAA iii ciclici iii a Application 3K Ke ex ui nain mm h as 10 ca Description This is the standard entry point for C code It is assumed the N app_cio zi main once you have performed all necessary 68HC12 and C initi S app_hooks c 19 0 om Arguments i none M app_probe c 380 40 0 ex BE EJE JE JE E JEJEJEJE E JEJEJEJE JEJEJEJE E EIE JEJE JE JEJEJEJE JEJEJEJE JE JEJEJEJE JE JEJEJEJE JE JEJEJEJE JEJEJEJE JE JEJEJEJE JE JEJEJEJE JEJEJEJE III MD includes h 0 0 zi MD os_cfah 0 0 zi AB probe_com_cfa h 0 0 zi void main void ND vectors e 256 0 eg fy BSP 1K 9e exi INT8U err H E uC CPU 8 0 om 9 uC LIB 1K 0 og A i CQ uC LCD 840 108 2 2 re Tart EQ uC 05 I 13K Keo omi OSTaskCreateFxt AnbStartTask E UC Probe x Sl mi OSTaskCreateExt AppStartTask m Startup Code 62 Goe om askStk APP_TASK_START_STK_SIZE 1 EQ Pim 0 Oe a SUKA BE TASKE STARI SIAE 1 E Linker Map 0 D a E Libraries 19K Ke exi kStk 0 E Debugger Project File 0 0 zi E Debugger Cmd Files 0 0 zi TK CHK OS_TASK_OPT_STK_CLR OSTaskNameSet APP TASK To PRIO Start Task amp err oSStart Star SPAGE ya BE EIE JEJE E JEJEJEJE JEJEJEJE JE JEJEJEJE E JEJEJEJE JE JEJEJEJE FEIE JEJEJE JEJEJ
5. for pC Probe Specifically this directory contains the following files os_probe c os_probe h Application Code 10 Micripm pC OS Il uC LCD and pC Probe for the Freescale MC9S12DG256 Micrium Software EvalBoards Freescale MC9S12DG256B Wytec Dragon12 Metrowerks Paged OS Probe LCD This directory contains the Freescale Codewarrior project file for the AN 1456 OS Probe LCD mcp Micrium Software EvalBoards Freescale MC9S12DG256B Wytec Dragon12 Metrowerks Paged OS Probe LCD Source This directory contains the source code for an example running on the Dragon12 Plus evaluation board It assumes the presence of pC OS II This directory contains app c app_cfg h app_hooks c app_probe c datapage c includes h os_cfg h probe_com_cfg h Start12 c vectors c app c contains the application entry point main and example code app_cfg h contains application specific configuration information such as task priorities and stack sizes It is highly recommended that users continue to use the app_cfg h for all application configuration constants instead of placing defines within several different files App_hooks c contains application software hooks for many OS functions such as context switching and idle task iterations piC Probe makes use of the pC OS II hooks in order to use idle processor time for making various measurements App_probe c contains initialization code for pyC Probe Includes h is a master include file used by
6. the application It is recommended but not necessary that users include additional files from includes h os_cfg h is the pC OS II configuration file Unused features of the operating system may be disabled from within this file in order to reduce the ROM and RAM footprint of the OS By default all features are enabled and the OS ticker is configured to run 1000 times per second This equates to a timer resolution of 1 millisecond Probe_com_cfg h is a configuration file for yC Probe By default u C Probe has been configured for task priority 9 a stack size of 160 bytes a receive buffer of 64 bytes and configured to use SCI1 Any of these configuration values including SCI selection may be changed if necessary Datapage c and start12 c are provided by Codewarrior but have been placed in the application directory for code warrior project consistency purposes 11 Micripm pC OS Il uC LCD and pC Probe for the Freescale MC9S12DG256 Micrium Software EvalBoards Freescale MC9S12DG256B Wytec ragon12 Metrowerks Paged BSP This directory contains the Board Support Package for the Dragon12 Plus evaluation board Some of the code in this directory may work on other MC9S12 derivatives however routines that are hardware dependent such as LED On will require modification depending on the hardware design of the EVB Please see the section labeled Board Support Package and Porting to Other MC9S12 Derivatives for more information
7. to see if its value is 1 If so then this is the only interrupt in progress and no nested interrupts are pending completion If interrupt have been nested skip storing the current tasks stack pointer back into its task control block and jump to MyISR1 Note the name of the ISR and the labels used within it must be changed for each new ISR implemented in the system For convenience the number 1 is added to the end of the ISR name in order to create a unique and convenient label to jump to If no interrupts have been nested then the scheduler is free to schedule a new task when the ISR completes Therefore the address of the current task TCB Task Control Block is obtained The stack pointer of the interrupted task is stored within its own TCB should the scheduler perform a context switch at the end of the ISR Call the user defined ISR handler Generally the ISR handler is defined and prototyped in C Re enable interrupts This is optional and allows interrupts to nest one another A performance gain may be difficult to obtain and in most cases nested interrupts are not necessary 34 Micripm uC OS II pC LCD and pC Probe for the Freescale MC9S12DG256 L3 4 18 Call oSIntExit This informs pC OS II about the end of the interrupt This is effectively the same as decrementing OSIntNesting however the scheduler is also invoked and if a context switch is required OSTntExit will not return L3 4 19 If a co
8. CLR if OS_TASK_NAME_SIZE gt 11 OSTaskNameSet APP START TASK PRIO Start Task amp err 5 endif OSStart 6 L2 1 1 As with most C applications the code starts in main L2 1 2 We start off by calling a BSP function see bsp c that will disable all interrupts We do this to ensure that initialization doesn t get interrupted in case we do a warm restart L2 1 3 As will all uC OS II applications you need to call OSInit before creating any task or other kernel objects L2 1 4 L2 1 5 L2 1 6 Micripm uC OS II pC LCD and pC Probe for the Freescale MC9S12DG256 We then create at least one task in this case we used OSTaskCreateExt to specify additional information about your task to wC OS II It turns out that uC OS II creates one and possibly three tasks in OSInit As a minimum uC OS Il creates a the idle task OS_TaskIdle Optionally the statistics task OS_TaskStat and the timer task OS_TmrTask are created if OS_STAT_EN and OS_TMR_EN are set to 1 within os_cfg h Both OS_TaskStat and OS_TmrTask are internal to wC OS II As of V2 6x you can now name uC OS Il tasks and other kernel objects and be able to display task names at run time or with a debugger In this case we name our first task Start Task We finally start uC OS II by calling oSStart pC OS Il will then start executing AppStartTask since that s the highest priority task cre
9. Communication 795 312 e xi 4 Generic 0 0e of Egos 0 0e nm Eq uC 0S l 0 0 mi AB probe_com_os c 0 0 exi Eg RS 232 795 312 e xi EE30S 143 162 xi M probe_rs232_os c 143 1620 xi 4 Port 128 0e exi MC9512 128 0 e ex RA probe_rs232c c 98 0 ex AN probe_rs232c h 0 Oe a AB probe_rs232_ba s 30 0 exi EE Source 524 150 xf RR probe_rs232 h 0 0 zi AB probe_rs232 c 524 150 xi 3 63 Plugins 652 587 e xi AB os_probe h 0 O zi AB os_probe c 652 597 e x 15 Micripm pC OS Il uyC LCD and uC Probe for the Freescale MC9S12DG256 Eq Source 1K ae om S probe_com h 0 0 zi probe_com c 1162 27 0 ex B Startup Code 62 Be exi MH Static 62 Be ex Sa Pm 0 0 a SD bumer bbl n a nwa zi SD P amp E_Multilink_CyclonePro_linker prm nza nza zi SD HCS12_Serial_Monitor_linker prm nza nwa zi BE Linker Map 0 D zi SD P amp E_Multilink_CyclonePro map nza n a zi SD HCS12_Serial_Monitor map nza n a a Bg Libraries 19K a e ex SD me9s12dq256 h 0 Oe zi SD mc9s12dg9256 c 0 400 xi BM ansib lib 19278 2019 zi MD datapage c 185 Oe ex Ea Debugger Project File 0 D zi SD P amp E_Multilink_CyclonePro ini nza nza a S HCS12_Serial_Monitor ini n a n a a BE Debugger Cmd Files 0 0 zi HE P amp E_Multilink_CyclonePro 0 0 a RA P amp E_Multilink_CyclonePro_Start nza nza zi S P amp E_Multilink_CyclonePro_Res nza n a a S PRE_Multilink_CyclonePro_Prel n a n a zi S P amp E
10. EJE JE JEJEJEJE JE JEJEJEJE JEJEJEJE JE JEJEJEJE JE JEJEJEJE JE IEI JEJE JEEE JEJE JEIJE JEIEN STARTUP TASK j Description This is an example of a startup task As mentioned in the book 78 files 42K 8K initialize the ticker only once multitasking has started wi Di Line 389 Co5 sf 6 Once the application has been loaded there are two options 7 a Press the green arrow within the debugger to launch the application in debug mode b Change the left SW7 to the up position RUN mode close the debugger and reset the target This will cause the application to run in stand alone mode Additionally you may visit the Micrium web site www micrium com and download the latest trial version of wC Probe wuC Probe allows global variables to be graphically mapped via a Windows application to various counters gauges spreadsheets switches and knobs for both viewing and changing during run time If uC Probe is utilized a second serial cable will need to be attached between the PC and SCl1 of the Dragon12 Plus EVB See the section labeled yiC Probe for more information Micripm pC OS Il uC LCD and pC Probe for the Freescale MC9S12DG256 8 Once the application is running the LCD and seven segment displays should update After a short while the application will prompt the user via the LCD screen indicating that keypad entry is now possible 1 03 Hardware Configuration 1 Enable seven segment LED blocks by placing J24A an
11. Instructions 1 Unzip AN1456 to c This will result in the c Micrium directory being created It is recommended that you unzip to the default directory since it adheres to AN2002 Directory Structure and makes supporting applications easier It also provides for a consistent directory structure with regards to version controlling several projects that share the same base code 2 Open the project file using Codewarrior version 4 5 or better The project file is located in the following directory and is named OS Probe LCD mcp Micripm uC OS II pC LCD and pC Probe for the Freescale MC9S12DG256 Micrium Software EvalBoards Freescale MC9S 12DG256B Wytec Dragon12 Metrowerks Page OS Probe LCD Ensure that the Dragon12 Plus Run Load switch is in the LOAD position This may be accomplished by switching the left hand switch of SW7 to the down position 4 Ensure that the current build configuration is set for HCS12 Serial Monitor This can be verified by viewing the pull down box above the source code tree illustrated in the screen shot below 5 Build and load the application by clicking on the green debug bution illustrated by the red arrow Freescale CodeWarrior app c 18 xj IB Fie Edit View Search Project Processor Expert Window Help l x LI A KE YA Ya AKA EEE 05 Probe LCD mcp 2 be gem E fl gt Path CAMicrium Soltware EvalBoards Freescale MC9512DG2568 Wytec Dragon12 M
12. Micrium Empowering Embedded Systems uC OS II uC LCD uC Probe and The Freescale MC9S12DG256 Using the Wytec Dragon12 Plus Evaluation Board Application Note AN 1456 www Micrium com Micripm uC OS II pC LCD and pC Probe for the Freescale MC9S12DG256 Table Of Contents 1 00 Introduction 3 1 01 Source code access 4 1 02 Quick Start Guide 4 1 03 Hardware Configuration 6 1 04 Port Specific Details 6 1 05 uC Probe 7 1 06 Directories and Files 9 1 07 Codewarrior IDE 14 2 00 Example Code 17 2 01 Example Code app c 17 2 02 Example Code app_cfg h 23 2 03 Example Code includes h 23 2 04 Example Code os_cfg h 23 3 00 Board Support Package BSP 24 3 02 Board Support Package bsp 24 3 03 Configuring the PLL 30 3 04 Vectors c 32 3 05 Creating Interrupt Service Routines 33 4 00 Porting to Other MC9S12 Derivatives 35 4 01 Additional Reading 36 Licensing 36 References 37 Contacts 37 Micripm pC OS Il uC LCD and uC Probe for the Freescale MC9S12DG256 1 00 Introduction This document shows example code for using pC OS II pwC LCD and uC Probe on a Freescale MC9S12DG256 processor To demonstrate the MC9S12DG256 we used a Wytec Dragon12 Plus Evaluation Board as shown in Figure 1 1 We used the Freescale Codewarrior IDE version 4 5 and Freescale Serial Monitor to compile and load this application However other tool chains may be used sare agauas iaia aaa ee ai vence sares sessa ceca seses se sis
13. Probe If you plan to run pC Probe with a different RTOS or without any RTOS the following files would have to be adjusted accordingly probe_com_os c C Micrium Software uC Probe Target Communication Generic RS 232 OS uCOS II This directory contains OS dependent interface code for the RS 232 specific portion of uC Probe specifically the code necessary to generate an optional Rx packet parse task If you plan to run pC Probe with a different RTOS modifications to the files listed below will have to be made If you are not running an RTOS the following files may be excluded from the build probe_rs232_os c C Micrium Software uC Probe Target Communication Generic RS 232 Ports Freescale MC9S 12 This directory contains the piC Probe hardware port files for the MC9S12 processor probe_rs232c c probe_rs232c h probe_rs232_ba s C Micrium Software uC Probe Target Communication Generic RS 232 Source This directory contains target independent source code for the pyiC Probe RS 232 communication layer Specifically this directory contains the following files probe_rs232 c probe_rs232 h C Micrium Software uC Probe Target Communication Generic Source This directory contains target independent source code for the wC Probe communication layer Specifically this directory contains the following files probe_com c probe_com h C Micrium Software uC Probe Target Plugins uCOS II This directory contains the target independent source code
14. Rate void Set_SCI_BaudRate INT32U baud CPU_INT32U baudDiv 1 baudDiv BSP_CPU_ClkFreq 2 baudDiv 2 baud 16 3 SCIOBDH baudDiv gt gt 8 4 SCIOBDL baudDiv amp OxFF 5 L3 4 1 Declare a 32 bit unsigned variable to hold the current SYSCLK frequency L3 4 2 Call BSP_CPU_ClkFreg in order to obtain the current SYSCLK frequency L3 4 3 Divide the SYSCLK frequency by 2 in order to obtain the BUSCLK frequency Note the SCl s reference clock is derived from BUSCLK Next divide the BUSCLK frequency by 16 to account for the SCI over sampling The is mentioned in the SCI block documentation under the section for computing the SCI baud rate Finally divide by the desired baud rate to achieve the SCI divider that corresponds to the specified baud rate and the current MCU operating frequency If you look closely the division by 2 16 and the desired baud was optimized in order to reduce the amount of truncation Truncation on smaller dividers such as 6 78 for 115 200 baud given BUSCLK 24MHz can be significant The actual baud rate after truncation would be BUSCLK 2 16 6 125 000 baud which corresponds to an 8 error rate which is acceptable for many UARTS If necessary take the ceiling of fractional dividers It s better to operate too slowly than too fast L3 4 4 Write the high byte of the divider to the baud rate high byte register L3 4 5 Write the low byte of the divider to the baud ra
15. SFlagPend keypadEnFlagGrp 0x01 OS_FLAG_WAIT_SET_ALL 0 amp err 4 key KeypadReadPort 5 if key OxFF 6 err sprintf out_str Keypad is IDLE else err sprintf out_str You Pressed c key_map key Dispstril 0 cut_str 7 OSTimeDlyHMSM 0 0 0 100 8 L2 5 1 Initialize the keypad BSP L2 5 2 Create a flag group used to signal between the LCD_TestTask and the keypadRdTask when access to the bottom row of the LCD is permitted L2 5 3 Wait block until the LCD_TestTask posts the flag L2 5 4 Check the flag to ensure access to the LCD is still permitted If the flag remains clear then the task will continue into the task body Upon each iteration of the loop 22 Micripm uC OS II pC LCD and pC Probe for the Freescale MC9S12DG256 the flag is checked to ensure that access to the LCD has not been revoked by the LCD_TestTask L2 5 5 Read the keypad If a button is pressed a value between 0 and 15 will be returned Otherwise OxFF is returned L2 5 6 If no keys have been pressed create the string The keypad is IDLE Otherwise look up which key character is pressed within the key map array and create the string You Pressed lt char gt L2 5 7 Print the correct string to the bottom row of the LCD L2 5 8 Repeat the keypad polling process every 100 milliseconds until blocked by the Keypad_TestTask 2 02 Example Code app_cfg h This file is used
16. _Multilink_CyclonePro_Post nza n a zi SD P amp E_Multilink_CyclonePro_Vpp n a n a zi SD P amp E_Multilink_CyclonePro_Vpp nza nza zi S P amp E_Multilink_CyclonePro_Eras nza n a zi B 3HCS12_Serial_Monitor 0 Oe a MD HCS12_Serial_Monitor_Startup n a n a e zi SD HCS12_Serial_Monitor_Reset c n a n a zi RR HCS12_Serial Monitor Preload nza n a zi RM HCS12_Serial_Monitor_Postloa nza nza ay 78 files 42K 8K 4 Figure 1 3 Complete Codewarrior Source Tree 16 Micripm pC OS Il uC LCD and pC Probe for the Freescale MC9S12DG256 2 00 Example Code As mentioned in the previous section the example code for this board is found in the following directories and will be briefly described Micrium Software EvalBoards Freescale MC9S12DG256B Wytec Dragon12 Metrowerks Paged OS Probe LCD It should be noted that processor header files and libraries are not included within the AN 1456 code archive since they are supplied by Freescale via the Codewarrior installation 2 01 Example Code app c app c demonstrates some of the capabilities of pC OS II Listing 2 1 main void main void 1 INT8U err BSP_IntDisAll 2 OSInit 3 OSTaskCreateExt AppStartTask 4 void 0 OS_STK amp AppStartTaskStk APP START TASK SIK SIZE 1 APP_START_TASK_PRIO APP_START_TASK_PRIO OS STK amp AppStartTaskStk 0 APP_START_TASK_STK_SIZE void 0 OS_TASK_OPT_STK_CHK OS_TASK_OPT_STK_
17. alue reaches the value stored within the timer channel match register After an interrupt occurs the match register is incremented to the next value for which a time tick interrupt is desired The timer is allowed to free run and overflow without error when necessary TCNT Interrupt on TCx Match OxFFFF 0x0000 1 Millisecond Figure 3 1 OS Tick Timer Operation When the selected Timer issues an interrupt the processor vectors to OSTickISR which has been specified in vectors c and is located within os_cpu_a s The ISR handler performs the necessary OS handling steps and then calls a C handler function named OSTickISR_Handler located within bsp c as described above in Listing 3 3 You should note that ALL of your ISRs should be written in assembly where OS related processing may take place before calling an interrupt handler function of the form interrupt void MyISR_Handler void See the section labeled Creating Interrupt Service Routines for more information 29 Micripm pC OS Il uC LCD and pC Probe for the Freescale MC9S12DG256 3 03 Configuring the PLL The PLL is an on chip peripheral capable of boosting the processor clock and bus frequencies higher than the frequency provided by the supplied oscillator across the XTAL pins of the MCU Before attempting to reconfigure the PLL from bsp h you should consult your MC9S12 derivative datasheet and understand the MCU s absolute maximum ratings The absolute
18. as s aa aa ZZZ voto s suo aus nuo manna deere H ee en ee AA EA ll ses t por lt a SA e smene Me oe lg AA N 5 Figure 1 1 Wytec Dragon12 Plus Evaluation Board The application code is downloaded into flash memory using the Freescale serial monitor application The serial monitor has been preinstalled within the MC9S12 flash memory prior to shipping from Wytec In order to download the demonstration application to the MC9S12 the host PC must have an available serial port If a serial port is unavailable it is possible to download and debug the application using a P amp E Multilink BDM and changing the project configuration settings found above the build tree from HCS12 Serial Monitor to P amp E Multilink Cyclone Pro Once the application has been loaded into the MCU flash memory the user may either run the application from the debugger or switch the EVB to RUN mode and press reset Once the application is running the onboard LCD and seven segment displays will update After a few seconds the user will be prompted via the LCD that the keypad is available for use Keys pressed during this time will be displayed on the bottom row of the LCD Micripm pC OS Il uC LCD and pC Probe for the Freescale MC9S12DG256 1 01 Source code access This application note describes a demonstration application using pC OS II uC LCD and uC Probe and is based on uC OS II Version 2 86 Micri
19. ated OSStart does not return Listing 2 2 AppStartTask static void AppStartTask void p_arg void p_arg 1 BSP_Init 2 if OS_TASK_STAT_EN gt 0 OSStatInit 3 endif if uC_PROBE_OS_ PLUGIN gt 0 uC_PROBE_COM MODULE gt 0 4 AppProbelInit endif AppTaskCreate 5 while TRUE 6 OSTimeDlyHMSM 0 0 0 500 7 L2 2 1 L2 2 2 L2 2 3 L2 2 4 L2 2 5 void p_arg prevents a common compiler warning which says that p_arg is not referenced anywhere in the code BSP_Init is called to initialize the Board Support Package the I Os the tick interrupt and so on BSP_Init will be discussed in the next section OSStatInit initializes the statistics task which is responsible for counting context switches and so fourth OS_TASK_STAT_EN inos_cfg hissetto 1 This function is called in order to initialize pC Probe The UART baud rate is configured from within app_probe c as 115 200 baud by default This call may be removed along with the pC Probe files if yC Probe functionality is not required Create additional application tasks through the use of a user supplied function named AppTaskCreate From here tasks for updating the LCD seven segment display and reading the keypad are created 18 L2 2 7 L2 2 8 Micripm uC OS II pC LCD and pC Probe for the Freescale MC9S12DG256 As with ALL task managed by pC OS II the task must either e
20. ble output compare interrupts on the desired ECT channel Start the timer Listing 3 3 Tmr_TickISR_Handler void OSTickISR_Handler void if OS_TICK_OC 1 TFLG1 0x01 2 TCO endif OSTickCnts 3 if OS_TICK_OC 1 TFLG1 0x02 TOA endif OSTickCnts if OS_TICK_OC 2 TFLG1 0x04 TC2 fendi f OSTickCnts if OS_TICK_OC TFLG1 0x08 TCS fendi f OSTickCnts if OS_TICK_OC 4 TFLG1 0x10 TC4 fendi f OSTickCnts 27 Micripm uC OS II pC LCD and pC Probe for the Freescale MC9S12DG256 if OS_TICK_OC 5 TFLG1 0x20 TES OSTickCnts endif if OS_TICK_OC TFLG1 0x40 TC6 OSTickCnts fendi f if OS_TICK_OC TFLG1 0x80 TC7 OSTickCnts fendi f OSTimeTick 4 This function is called from an assembly interrupt service routine which informs pC OS II of the interrupt and calls the C code interrupt handler See os_cpu_a s and the section labeled Creating Interrupt Service Routines for more information L3 3 1 If OS_TICK_OC is configured to 4 L3 3 2 Clear the interrupt source L3 3 3 Adjust the timer channel match register so that a new time tick will occur after OSTickCnts additional counts L3 3 4 Call oSTimeTick to inform wC OS II of the clock tick 28 Micripm pC OS Il uC LCD and pC Probe for the Freescale MC9S12DG256 The ECT generates match interrupt when the up counter v
21. ctor a C prototype in the form of extern void near MyISR void must be provided at the top of the vectors c file The name of the ISR may then be plugged into the correct location of the interrupt vector table The following vectors are used by piCc OS Il and should not be modified Vector 8 Standard Timer Channel 0 This ECT channel functions as a periodic interrupt for driving the seven segment display Vector 15 Standard Timer Channel 7 This may be adjusted to one of the other Standard Timer Channel vectors if desired See the section labeled Porting to Other MC9S12 Derivatives for more information Vector 21 SCI1 The selected communication port for uC Probe Vector 20 SCIO may be used instead of SCI1 if desired However the serial monitor uses SCIO by default therefore loading and debugging would have to occur using a BDM in order to free up the additional SCI If the uC Probe default SCI port is changed then prob_com_cfg h will need to be adjusted accordingly 32 Micripm pC OS Il uC LCD and pC Probe for the Freescale MC9S12DG256 3 05 Creating Interrupt Service Routines All interrupt service routines must contain a short assembly routine The address of the assembly routine is used to plug the interrupt vector table while the content is designed to notify uC OS Il of the interrupt and call the user supplied interrupt handler written in either assembly or C code The prototype specified at the t
22. d in the uC Probe target directory 3 Connect Target to PC Currently pC Probe can use RS 232 to retrieve information from the target You should connect a RS 232 cable between your target and computer Load Your ELF File The example projects included with this application note are already configured to output an ELF file If you are using your own project please refer to Appendix A of the uC Probe user manual for directions for generating an ELF file with Micripm uC OS II pC LCD and pC Probe for the Freescale MC9S12DG256 your compiler Codewarrior generates an ELF file with an abs extension This file is located in a directory named BIN within the sample project directory To load this ELF file right click on the symbol browser and choose Add Symbols Navigate to the file directory select the file and choose OK 4 Configure the RS 232 Options In pC Probe choose the Options menu item on the Tools menu A dialog box as shown in Figure 6 2 left should appear Choose the RS 232 radio button Next select the RS 232 item in the options tree and choose the appropriate COM port and baud rate The baud rate for the project accompanying this application note is 115 200 5 Start Running You should now be ready to run pC Probe Just press the run button gt to see the variables in the open data screens update 1 06 Directories and Files The code and documentation of the port are placed in a
23. d removing J24B 2 Enable SCI1 for RS232 communication by setting J23 to position 2 the SCI1 setting 3 Set the left switch of SW7 to the down position to enable LOAD mode Once the application is running and debugging is no longer necessary the user may move the left SW7 switch to the up position to enable RUN mode From this mode the MCU serial monitor will automatically start the user application upon power up Pins in use 1 PortA on board keypad 2 Port B seven segment LED blocks 3 Port K character LCD 4 PSO through PS3 SCIO for the serial monitor and SCI1 for pC Probe 1 04 Port Specific Details This pC OS II processor port has been designed to operate in the MC9S12 banked memory model Paging must not be enabled within the Codewarrior project options since the PPAGE register save and restore functionality has been included in the yiCc OS Il port Additionally this uwC OS II port has been customized to work in conjunction with the Freescale serial monitor application As a result this port will NOT work when the MCU is in expanded mode since the ability to use SWI to perform context switches has been replaced with the JSR opposed to the CALL instruction Applications that are loaded and run without the serial monitor are encouraged to use the non serial monitor compliant port as it offers slightly improved context switch performance via SWI This application assumes the presence of an 8MHz crystal on the Dragon12 Plus
24. directory structure according to AN 2002 uC OS Il Directory Structure Files for the banked serial monitor and non serial monitor compliant ports have been supplied by Micrium Specifically the files are placed in the following directories yC OS II Micrium Software uCOS IISource This directory contains the processor independent code for uC OS II The version used was 2 86 Micrium Software uCOS II Ports HCS 12 Paged Metrowerks Micrium Software uCOS II Ports HCS12 Paged Metrowerks SerialMonitor These directories contain the standard processor specific files for a wC OS II port assuming the Freescale Codewarrior IDE These files could easily be modified to work with other tool chains however you would place the modified files in a different directory Only one processor port non serial monitor compliant or serial monitor compliant may be compiled in to a pC OS II project at any given time When switching ports it is necessary to remove the old port files from the build tree add the new port files and adjust the access path settings to ensure that Codewarrior does not observe header files from the old port directory Specifically the required files are os_cpu h os cpu a s os_cpu_c c pC Probe Micripm uC OS II pC LCD and pC Probe for the Freescale MC9S12DG256 C Micrium Software uC Probe Target Communication Generic OS uCOS II This directory contains the OS dependent interface for the communication layer of uC
25. ent on system bus frequency The ECT timer TCNT is a 16 bit up counter The match register used to create the uC OS Il time tick is also a 16 bit value If the timer operates too quickly then the number of time ticks necessary to obtain the desired OS TICKS PER SEC see os_cfg h will overflow during the call to OSTickISR_Init Therefore the ECT prescaler must be increased from the default value when the PLL is active L3 1 2 This function initializes the on chip PLL First the multiplier and divider are configured then the PLL is enabled and finally the system clock is switched from the main oscillator to that of the PLL output L3 1 3 Adjust the ECT prescaler if the PLL is enabled to prevent an overflow of OSTickCnts during the call to OSTickISR_Init L3 1 4 Initialize the selected ECT channel for use with the uC OS II time tick interrupt The code for this function is described below L3 1 5 Initialize the general purpose I O pins used for controlling the onboard LEDs L3 1 6 Determine the CPU clock frequency in Hz during run time It is highly recommended that application code make use of this function in order to program system dividers during runtime This prevents the user from having to change all hard coded divider values should the clock frequency need to be modified at a later time Note The system bus frequency is the CPU clock frequency divided by 2 Some module input clocks use the CPU clock as a reference while othe
26. itialize the seven segment display BSP The seven segment display BSP initiates a periodic ECT channel interrupt which writes the specified value to the seven segment display blocks every time the interrupt occurs This functionality is independent of calling SevenSegWrite which only updates the value to be 21 Micripm uC OS II pC LCD and pC Probe for the Freescale MC9S12DG256 displayed until the next call to SevenSegWrite The ECT channel used may be changed within app_cfg h L2 4 2 Write an initial starting value to the seven segment display L2 4 3 Increment the number to be displayed next by one keeping it between 0 and 9999 L2 4 4 All wC OS II tasks must either enter an infinite loop waiting for some event to occur or terminate itself In this case we wait for time to expire as the event This is accomplished by calling OSTimeD1yHMSM with a timeout of 10 milliseconds Listing 2 5 KeypadRdTask static void KeypadRdTask void p_arg CPU_INTO8U key CPU_INTO8U out_str 17 CPU_INTO8U key_map 1 2 3 A tat Voto et UB ts Uta VO VON LG TE 0 tt D CPU_INTO8U err void p_arg KeypadInitPort A keypadEnFlagGrp OSFlagCreate 0 amp err 2 while err OS_NO_ERR OSTimeDlyHMSM 0 0 1 0 keypadEnFlagGrp OSFlagCreate 0 amp err OSFlagPend keypadEnFlagGrp 0x01 OS FLAG WAIT SET ALL 0 amp err 3 DispClrLine 1 while DEF_TRUE O
27. lator frequency In general lower clock speeds require less operating power The operating frequency of the MC9S12DG256 must never fall below 8MHz with the PLL enabled When enabling the PLL on the MC9S12DG256 the highest possible value for PLL_CLK_MUL is 3 while the lowest possible value of PLL CLK DIV is 0 Plugging these register values into the above equation yields the following SYSCLK 8 000 000 2 3 1 0 1 48MHz 1 1 48MHz BUSCLK SYSCLK 2 24MHz The BSP function BSP_CPU_C1kFreq yields the current SYSCLK frequency and is the preferred method for determine the system operating frequency during run time 30 Micripm pC OS Il uC LCD and pC Probe for the Freescale MC9S12DG256 Note BSP_CPU_C1kFreq returns a 32 bit unsigned integer representation of the SYSCLK frequency Dividing this value by 2 will yield the BUSCLK frequency It is recommended that users call this function before programming peripheral clock dividers so that the dividers need not be re evaluated should the clock frequency be adjusted at a later time This method is used when computing the wC OS II tick number of counts during initialization and when computing the baud rate for pC Probe It is important to note that most but not all MC9S12 peripherals use the BUSCLK as a reference clock source An example of divider initialization based on an unknown operating frequency may be performed as follows Listing 3 4 Set_SCl_Baud
28. ling the about message from right to left This short loop shifts the message by one character until the white space to the left of the string has been filled by incoming characters Once the string has filled the top row of the LCD continue to shift the string left to create a scrolling effect until the end of the string is near Shift the remaining characters off of the LCD and fill the training characters with spaces to have them appear empty This gives the illusion that the string is scrolling off of the LCD Clear the LCD ownership flag indicating to the keypadRdTask that control of the LCD is being returned to the LCD_TestTask The keypadRdTask will continue to execute until it wraps around the task body and pends on the flag group Check for errors while posting to the flag group This code is optional since no errors should occur while posting to the flag group however checking for errors is of course best practice If an error does occur the application will attempt to repost the flag every second until successful Clear both rows of the LCD Flash the keypad disabled string three times with a half second in between screen updates Listing 2 4 SevenSegTask static void SevenSegTestTask void p_arg CPU_INT 16U num void p_arg SevenSegDisp_Init 1 num 0 while DEF_TRUE SevenSegWrite num 2 num num 1 10000 3 OSTimeDlyHMSM 0 0 0 10 4 L2 4 1 In
29. maximum ratings must be followed in order to prevent the possibility of damaging the device The MC9S12DG256 has a maximum processor clock SYSCLK of 50MHz The bus clock BUSCLK is always 2 of the processor clock and must never exceed 25 MHz The oscillator supplied on the Dragon12 Plus is 8MHz which means that the highest stable clock frequency for this EVB is 48MHz with a 24MHz bus frequency Note The input oscillator frequency is automatically doubled before entering the PLL Therefore the highest possible PLL multiplier is 4 which effectively multiplies the 16MHz 8MHz 2 input frequency by 4 this creating a 48MHz CPU clock frequency The PLL may be configured by adjusting the following macros within bsp h OSCFREQ PLL_EN PLL_CLK_MUL PLL_CLK_DIV The output frequency is computed by the following formula OSCFREQ 2 PLL_CLK_MUL 1 PLL_CLK_DIV 1 Where OSCFREQ is the frequency of the oscillator attached to the XTAL pins of the MCU In the case of the Dragon12 Plus OSCFREQ equals 8 000 000 Hz The PLL may be disabled by setting the value of PLL_EN to 0 The example provided is capable of running with the PLL either enabled or disabled High performance applications may wish to enable the PLL while power aware devices such as portable electronics may wish to run the device with the PLL disabled or with an increased divider thereby lowering the overall frequency below the supplied oscil
30. nter an infinite loop waiting for some event to occur or terminate itself Delay the task for 500 milliseconds and repeat the contents of the while loop indefinitely Even though AppStartTask serves as the system startup task it may be used as a general purpose task In this particular case the task body has been left empty and thus may be utilized by the user s application if desired Otherwise the task could delete itself and a new task could be created that utilizes the startup tasks stack space Listing 2 3 LCD_TestTask static const const const const void LCD_TestTask void p_arg CPU_INTO8S i CPU_INTO8U err CPU_INTO8U KeypadEnStr 18 CPU_INTO8U KeypadDisStr 18 Keypad Enabled 1 Keypad Disabled CPU_INTO8U WelcomeStr 6 18 Welcome to the Dragon 12 EVB Wa This demo runs Micrium uC OS II on a 48 MHz MC9S12DG256B CPU CPU_INTO8U aboutStr Did you know that uC OS II can provide multi tasking and real time services to your embedded applications In fact uC OS II provides services such as task delays semaphores message mailboxes timers event flags memory management mutexes queues and much more CPU_INTO8U aboutStrPtr void p_arg DispInit 2 16 2 while DEF_TRUE DispClrScr 3 for i 0 i lt 6 it 2 4 DispStr 0 0 WelcomeStr i DispStr 1 0 WelcomeStr i 1 OSTimeDlyHMSM 0
31. ntext switch is not necessary obtain the copy of PPAGE saved at the beginning of the ISR L3 4 20 Restore the PPAGE register L3 4 21 Return to the interrupted task 4 00 Porting to Other MC9S12 Derivatives Due to the similarities between various MC9S12 derivatives it is easy to port the sample application from one derivative to another The following steps must be performed in order to switch MCU derivatives Porting to different MC9S12 derivatives 1 Navigate to the project directory and open the project file using Codewarrior 2 Replace the processor header files in the source tree with those from the desired derivative Adjust includes h accordingly 3 Replace the CMD directory contents with the command files from a project built for the derivative of your choice 4 Obtain a prm file from a sample project belonging to the derivative of your choice The prm file contains linker configuration directives for the desired MCU derivative Replace existing the linker prm located in the below directory with the prm of the new derivative Note Generally Codewarrior defines the Startup vector in the prm file All interrupt vector references MUST be removed from the prm in favor of those already specified in vectors c 4 Update BSP c functions for LED_On LED_Off LED_Toggle etc to match your hardware configuration if required 6 Adjust the macro OSCFREQ within bsp h to account for a different oscillator frequenc
32. number 16 bit address and will overflow the slot in the interrupt vector table Define the address of the PPAGE register This register is memory mapped and located at address 0x30 on the MC9S12DG256 MCU XDEF is a Codewarrior assembly directive for prototyping external functions This directive is equivalent to extern in C and allows the assembler to find the address of the ISR handler specified below on line item 16 The name being XDEF d should match the name of your ISR handler whether it is written in assembly or C code This directive is not necessarily portable to other assemblers 4 5 6 and 7 are external references to variables defined in C These variables are referenced from the context of the assembly ISR and must therefore be declared external such that they are visible to the assembler and ISR file This directive is not necessarily portable to other assemblers Obtain a copy of the PPAGE register This register must be saved because the uC OS II is operating under the BANKED memory model Store the PPAGE register on the stack of the task that was interrupted Increment OSIntNesting This notifies wC OS II that at least one interrupt is in progress and that the scheduler should not schedule any new tasks to run until all nested interrupts have completed e g OSIntNesting equals 0 Load a copy of OSIntNesting from memory into a register so a comparison may be made Check OSIntNesting
33. on switches between Design and 3 800 Run Time Views 3 600 During Run Time View ane when data is collected this will 2 800 appear as a stop 2 600 button a blue square 2400 m 2 000 os_cpu c c os_probe c 1 800 os_time c 1 800 os_tmr c 1 400 probe_come i probe com os c 1 200 E probe_1s232 c 1 000 probe_1s232_os c 3 probe_1s232c c 900 ATSHCO8 C 600 J Start08 c 400 L vectors c Symbol Browser Data Screen Contains all symbols from the Components are placed onto the data screen and ELF files added to the assigned symbols during Design View During workspace Run Time View these components are updated with values of those symbols from the target Accelerometer Raw Data Accelerometer Raw Data CPU Usage 4 200 4 200 100 BHR FRAPPR RS 232 38400 COMI ss 315 symbols sec Figure 2 1 yC Probe Windows Program To use uC Probe with the example project or your application do the following 1 Download and Install piC Probe A trial version of pC Probe can be downloaded from the Micrium website at http www micrium com products probe probe html 2 Open pC Probe After downloading and installing this program open the example uC Probe workspace for uC OS II named OS Probe wsp which should be located in the AN 1456 Codewarrior project directory You may also open one of the sample workspaces that come with piC Probe The sample workspace files are locate
34. op of vectors c See section 3 04 above is the C code prototype for the following assembly interrupt service routine It is this prototype that allows you to plug the interrupt vector table with the name address of the ISR from C As areminder the prototype is written as follows extern void near MyISR void Of course the name of the ISR would change each time a new ISR is declared since two ISR s of the same name cannot exist in the system simultaneously The format of an interrupt service routine is as follows Listing 3 5 MyISR NON_BANKED section 1 PPAGE equ 0030 2 xdef MyISR_Handler 3 xref OSIntExit 4 xref OSIntNesting 5 xref OSTCBCur 6 xref OSView_RxTxISRHandler 7 MyISR ldaa PPAGE 8 psha 9 inc OSIntNesting 10 ldab OSIntNesting 11 cmpb 01 12 bne MyISR1 13 ldy OSTCBCur 14 sts O y 15 MyISRl call OSTickISR_Handler 16 cli 17 call OSIntExit 18 pula 19 staa PPAGE 20 rea 21 L3 4 1 Force the contents of the assembly file perhaps named myisr_a s into NON_BANKED memory This is critical since the processor only has a 16 bit address bus Vectors that are accidentally placed into banked memory will have a 24 bit 33 L3 4 2 L3 4 3 L3 4 4 L3 4 8 L3 4 9 L3 4 10 L3 4 11 L3 4 12 L3 4 13 L3 4 14 L3 4 15 L3 4 16 L3 4 17 Micripm pC OS Il uC LCD and pC Probe for the Freescale MC9S12DG256 address 8 bit page
35. rd will be placed into Flash memory and not in RAM Initialize wC LCD Generally if more than 1 task utilizes a particular module it should be initialized prior to either of those tasks running A good place to initialize such modules would be in the startup task In this particular case access to the LCD screen is protected by an OS flag group therefore since the LCD_TestTask is the primary owner of the LCD initialization occurs within this task however it could have been done elsewhere Clear the LCD screen Display the Welcome message two lines at a time with a two second delay between screen updates Clear the bottom line of the LCD At this point this task no longer requires both lines of the LCD Signal the keypadRdTask to awaken it so that it may read the keypad and show which key is being pressed on the bottom row of the LCD 20 L2 3 7 L2 3 8 L2 3 9 L2 3 10 L2 3 11 L2 3 12 L2 3 13 L2 3 14 L2 3 15 L2 3 16 Micripm pC OS Il uC LCD and pC Probe for the Freescale MC9S12DG256 Check for flag posting errors This code is optional since no errors should occur during the posting of the flag If an error does occur the application will attempt to repost the flag every second until successful Clear the top row of the LCD while the keypadRdTask is utilizing the bottom row Flash the Keypad enabled message three times with a half second delay in between Begin scrol
36. related to the BSP This directory contains bsp c bsp h keypad c keypad h sevenSegDisp c sevenSegDisp_OS c sevenSegment s sevenSegDisp h nvm c nvm h Vectors c bsp c contains hardware specific source code for LED services PLL initialization uC OS Il ticker initialization wC LCD hardware access routines uC Probe timer routines and general purpose functions for obtaining clock frequencies during run time It is highly recommended that utilize the BSP functionality and not hardcode clock dividers during build time bsp h contains macros for configuring the system PLL and uC OS Il time tick ECT channel Please see the section labeled Porting to Other MC9S12 Derivatives for more information related to the bsp h nvm c and nvm h contain hardware access functions for reading and writing both Flash and EEPROM during run time Neither of these files are used within the example but have been provided for convenience Special care should be taken when modifying the contents of Flash or EEPROM during run time as it may be possible to overwrite portions of the application accidentally vectors c contains the processor interrupt vector table This array of Interrupt Service Routine addresses must be updated whenever a new interrupt is being configured on the system Interrupt vectors that are not in use should be plugged with the appropriate Dummy ISR handler provided The serial monitor automatically copies user specified vectors in
37. rs use the bus clock Be sure to determine the correct clock for the module being initialized and use BSP_CPU_ClkFreq 2 when necessary L3 1 7 Convert the CPU clock frequency from Hz to KHz L3 1 8 Initialize the Flash memory access dividers Steps 6 through 8 are optional and are not present in the Dragon12 Plus BSP However including the nvm c and nvm h files and adding these lines either within the BSP or another part of the application will allow the user to change the content of either Flash memory or EEPROM during run time 25 Listing 3 2 OSTickISR_Init static void OSTickISR_Init INT32U cpu_frq INT32U bus_frq INT8U ECT_Prescaler void Micripm uC OS II p C LCD and pC Probe for the Freescale MC9S12DG256 cpu_frq BSP_CPU_ClkFreq 1 bus_frq cpu_frq 2 2 ECT_Prescaler TSCR2 amp 0x07 3 ECT_Prescaler 1 lt lt ECT_Prescaler 4 5 OSTickCnts INT16U bus_frq ECT_Prescaler OS_TICKS_PER_SEC 1 if OS_TICK_OC 0 6 TIOS 0x01 7 TCO TCNT OSTickCnts 8 TIE 0x01 9 endif if OS_TICK_OC TIOS 0x02 TCL TCNT OSTickCnts TIE 0x02 endif if OS_TICK_OC TIOS 0x04 TC2 TCNT OSTickCnts TIE 0x04 endif if OS_TICK_OC 3 TIOS 0x08 TES TCNT OSTickCnts TIE 0x08 endif if OS_TICK_OC TIOS 0x10 TC4 TCNT OSTickCnts TIE 0x10 endif if OS_TICK_OC TIOS 0x20 TC5 TCNT OSTickCnts TIE 0
38. te low byte register 31 Micripm pC OS Il uC LCD and pC Probe for the Freescale MC9S12DG256 3 04 Vectors c vectors c contains the interrupt vector table for the application The interrupt vector table is necessary so that the processor knows the address of the interrupt service routine to jump to when a specific interrupt occurs Failure to properly plug the interrupt vector table with the address of a valid handler may cause the application to crash If a wrong but valid interrupt handler address is specified for vector number n and the interrupt occurs the interrupt source will not be cleared and the processor will execute the same interrupt service routine indefinitely Care should be taken when working with the interrupt vector table For convenience dummy interrupt service routines have been provided for all 64 vectors This does not include the reset vector since its value must always be set correctly When an interrupt vector is not in use the dummy ISR for that vector should be plugged In the case of a spurious interrupt the processor will vector to the dummy ISR and loop indefinitely Should this occur you may be able to debug the application and catch the processor in the dummy interrupt service routine thus identifying the source of the spurious interrupt The correct action may then be taken to correct the application to prevent this type of error in the future When plugging the interrupt vector table with a new ve
39. to configure the pC OS Il task priorities of each of the tasks in your application the stack size for each task pC LCD some aspects of uC Probe 2 03 Example Code includes h includes h is a master header file that contains include directives to include other header files This is done to make the code cleaner to read and easier to maintain It is recommended that additional include files be included from within includes h 2 04 Example Code os_cfg h This file is used to configure pC OS II and defines the maximum number of tasks that your application can have which services will be enabled semaphores mailboxes queues etc the size of the idle and statistic task and more In all there are about 60 or so defines that you can set in this file Each entry is commented and additional information about the purpose of each define can be found in the pC OS II book os_cfg h assumes you have uC OS Il V2 85 or higher but also works with previous versions of pC OS II Micripm pC OS Il uC LCD and pC Probe for the Freescale MC9S12DG256 3 00 Board Support Package BSP BSP stands for Board Support Package and provides functions to encapsulate common I O access functions in order to make it easier for you to port your application code In fact you should be able to create other applications using the Dragon12 Plus evaluation board and reuse these functions thus saving you a lot of time Many of the provided f
40. to the serial monitor secondary vector table Micrium Software EvalBoards Freescale MC9S12DG256B Wytec Dragon12 Metrowerks Paged OS Probe LCD prm This directory contains the processor linker files When a new Codewarrior project is created the startup vector is automatically placed in the active project s linker file The user MUST remove all vectors from the prm files and use the provided vectors c instead Failure to remove the startup vector from the linker file will result in a linker error during 12 Micripm pC OS Il uC LCD and pC Probe for the Freescale MC9S12DG256 link time The linker file is derivative dependent If a different MC9S12 MCU is to be used please see the section labeled Porting to Other MC9S12 Derivatives below 13 Micripm pC OS Il uC LCD and uC Probe for the Freescale MC9S12DG256 1 07 Codewarrior IDE We used the Freescale Codewarrior IDE version 4 5 to compile and run the MC9S12DG256 example You can of course use uC OS Il with other tools Figures 1 3 shows the project source tree with all of the files necessary to build the example 0S Probe LCD mcp x E HCS12 Serial Monitor lia xy A y P amp E Multilink CyclonePro HCS erial Monitor e Fle Code Data 3 Sources 23K BK m Application 3K Ke of AB app c 3058 1370 xi AB app_cfo h 0 0 zi AB app_hooks c 19 0D
41. um s policy in regards to getting access to source code is as follows uC OS and uC OS Il source and object code can be used by accredited Colleges and Universities without requiring a license as long as there is no commercial application involved In other words no licensing is required if uC OS and uC OS Il is used for educational use You need to obtain an Object Code Distribution License to embed pC OS or pC OS II in a product that is sold with the intent to make a profit or if the product is not used for education or peaceful research You also need to obtain a Source Code Distribution License to distribute C OS or uC OS II in source code form For all the wC products other than wC OS II you need to obtain an Object Code Distribution License to get access to the source code 1 02 Quick Start Guide Prerequisites 1 Codewarrior 4 5 or better A valid license file must be present The standard demonstration Codewarrior license is limited to 32 files and will not be sufficient for compiling the provided application If you do not have a full featured license and belong to an academic institution one may be obtained by contacting Freescale support 2 Dragon12 Plus EVB 3 Available serial port on the host computer A standard UART is required by Codewarrior when using the serial monitor configuration to connect to MC9S12 MCU The cable should be connected between the host PC and SCIO on the Dragon12 Plus
42. uments may be found in the uC OS Il documentation directory located within c Micrium Software uCOS IT doc 7 QuickRefChart Color PDF An short summary of all pC OS II API functions 8 uCOS II RefMan PDF A detailed user manual for uwC OS II 9 uCOS II CfgMan PDF yiCc OS Il configuration guide Related to os_cfg h Licensing If you intend to use pC OS II in a commercial product remember that you need to contact Micrium to properly license its use in your product The use of uC OS Il in commercial applications is NOT FREE Your honesty is greatly appreciated Micripm pC OS Il uC LCD and pC Probe for the Freescale MC9S12DG256 References MicroC OS II The Real Time Kernel 2 Edition Jean J Labrosse CMP Technical Books 2002 ISBN 1 5782 0103 9 Sii CMP Books Inc Micrium 6600 Silacci Way 949 Crestview Circle Gilroy CA 95020 USA Weston FL 33327 Phone Orders 1 800 500 6875 USA or 1 408 848 3854 954 217 2036 Fax Orders 1 408 848 5784 954 217 2037 FAX e mail rushorders cmpbooks com e mail Jean Labrosse Micrium com WEB http www cmpbooks com WEB www Micrium com Freescale Technology Inc 2355 West Chandler Blvd Chandler Arizona 85224 6199 USA 480 792 7200 WEB www Freescale com 37
43. unctions are backward compatible with the standard Dragon12 The BSP performs the following functions Determine the MC9S12 CPU clock and bus frequencies Configure the LED I Os for the Dragon12 Plus EVB Configuration and handling of the uC OS II tick timer Configuration and handling of the yiC Probe measurement timer The BSP for the Dragon12 Plus is found in the follow directory Micrium Software EvalBoards Freescale MC9S12DG256B Wytec ragon12 Metrowerks Paged BSP This directory contains bsp c bsp h keypad c keypad h sevenSegDisp c sevenSegDisp_OS c sevenSegment s sevenSegDisp h nvm c nvm h Vectors c 3 02 Board Support Package bsp We will not be discussing every aspect of the BSP but only cover topics that require special attention Your application code must call BSP_Init to initialize the BSP BSP_Init in turn calls other functions when necessary Listing 3 1 BSP_Init void BSP_Init void INT32U sys_clk_frq 1f PLL_EN gt 0 1 PLL_Init 2 BSP_SetECT_Prescaler 4 3 24 Micripm pC OS Il uC LCD and pC Probe for the Freescale MC9S12DG256 fendi f OSTickISR_Init 4 LED_Init 5 sys_clk_frq BSP_CPU_ClkFreq 6 sys_clk_frq 1000 7 Flash_Init sys_clk_frq 8 L3 1 1 If PLL_EN is configured to 1 within BSP h the processor PLL will be initialized The conditional compilation for PLL initialization is necessary since the ECT is depend
44. x20 endif if OS_TICK_OC 6 TIOS 0x40 TC6 TCNT OSTickCnts TIE 0x40 endif if OS_TICK_OC 7 TIOS 0x80 TEJ TCNT OSTickCnts TIE 0x80 endif TSCR1 0xC0 10 26 L3 2 1 L3 2 2 L3 2 3 L3 2 4 L3 2 5 L3 2 6 L3 2 7 L3 2 8 L3 2 9 L3 2 10 Micripm pC OS Il uC LCD and pC Probe for the Freescale MC9S12DG256 Get the CPU operating frequency in Hz Divide the CPU frequency by 2 in order to obtain the bus clock frequency in Hz This value is used to calculate the correct number of timer increments for the desired OS Tick rate Determine the ECT prescaler value The ECT prescaler acts as a divider to the input clock of the ECT The higher the ECT prescaler the more slowly TCNT the ECT up counter register increments The ECT prescaler is an important piece of information when calculating required timer channel match value Convert the ECT prescaler register value into the decimal equivalent suitable for mathematical calculations E g Turn the bit pattern 01 into a prescaler value of 2 and so on Compute the number of timer increments necessary to generate the desired uC OS Il Tick rate If OS_TICK_OC in bsp h is defined as 4 then configure TC4 as the wC OS II tick source Configure the desired timer channel as an output compare Write the match register with the current value of the ECT counter TCNT plus the number of ticks until the next desired match Ena
45. y if applicable 5 Ensure that the PLL settings within bsp h are suitable for use within the new derivative If you are unsure disable the PLL temporarily until the proper settings can be determined Caveats 1 vectors c is provided as is and is assumed to be correct for some MC9S12 derivates Vectors can be added by prototyping the assembly ISR handler as an external at the top of the file and then plugging the correct array location with the name of the ISR routine See section 3 04 labeled Vectors c for more information 35 Micripm pC OS Il uC LCD and pC Probe for the Freescale MC9S12DG256 2 The example provided assumes the use of ECT TC7 for the OS Ticker If TC7 is not available this may be changed by adjusting the macro named OS_TICK_OC within bsp h and by adjusting vectors c and placing OSTickISR in the desired vector location 3 Start12 c may need to be replaced with an equivalent file from a project built for the derivative of your choice 4 01 Additional Reading 1 MicroC OS II The Real Time Kernel The following application notes are relatively short and provide detailed concept and usage examples for pC OS II These application notes have been bundled with AN1458 for convenience AN2000 C Standard AN1002 Mutex AN1004 10 Minute Guide to RTOS AN1005 Introduction to IPC Inter Process Communication AN1007 Event Flags Our wh The following doc
46. ymbols referenced within the users embedded application Only symbols that have been allocated memory e g not allocated on the stack are able to be monitored by uC Probe Global and static variables are examples of variables that may be monitored The user places components such as gauges labels and charts into a Data Screen in a uC Probe workspace Each one of these controls is then assigned to one or more of the variables from the Symbol Browser The Symbol Browser lists all symbols referenced from within the ELF file Symbols associated with components placed on an open Data Screen will be updated after the user presses the start button assuming the user s PC is connected to the target and the target is running uC Probe currently interfaces with a target processor via JTAG RS 232 UDP and USB A small section of code resident on the target receives commands from the Windows application and responds to those commands The commands ask for a certain number of bytes located at a certain address for example Send 16 bytes beginning at 0x0040102C The Windows application upon receiving the response updates the appropriate component s on the data screen s with the new values Micripm uC OS II pC LCD and pC Probe for the Freescale MC9S12DG256 E Micrium pC Probe probe_example wsp 51 x i Eile Tools Help Alb B B B B ale Bi B B plorer 9 MC9508 Demonstration I nic Start Stop button This butt
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