RM-PICC18 Salvo Compiler Reference Manual – HI
Contents
1. RUE Bi per 3 RUE B sistent Example salvocfg h for Source Code Build 378 618 696 1462 2374 2658 1994 total ROM total RAM Table 5 ROM and RAM requirements for Salvo Applications built with HI TECH s PICC 18 C Compiler Special Considerations Stack Issues For architectural reasons HI TECH s PICC 18 C compiler does not pass parameters on the stack Nor does it allocate memory for auto local variables on the stack Instead it employs a static overlay model This has advantages in speed and memory utilization but it precludes recursion and has other impacts RM PICC18 Salvo Compiler Reference Manual HI TECH PICC 18 The RTOS that runs in tiny places Reference Manual Multiple Callgraph Issues 10 By default it is expected that Salvo services will only be called from the background main loop task level This is the default configuration for source code builds b variant libraries allow service calls only from the background level Should you wish to call certain services from the foreground interrupt level you will need to set OSCALL_OSxyz configuration options for source code builds or use a different library see Table 3 for library builds From Variant above we find that the f variant libraries allow you to call event reading and signaling services from the foreground Similarly the a variant libraries allow you to call the applicable services from anywhere2. In this case the PICC 18 C compiler is linking to its pic821 c 1ib library in order to build the application Therefore RM PICC18 Salvo Compiler Reference Manual HI TECH PICC 18 5 The RTOS that runs in tiny places Memory Model Configuration Variant Reference Manual the appropriate target code for the Salvo library is 82 e g sfp82leb 1lib The HI TECH PICC 18 C compiler s small and large memory models are supported In library builds the memory model applied to all of the source files must match that used in the library For source code builds the same memory model must be applied to all of the source files Note Unlike the library configuration and variant options specified in the salvocfg h file for a library build none is specified for the selected memory model Therefore particular attention must be paid to the memory model settings used to build an application The memory model is usually specified on a node by node basis inside an IDE e g MPLAB Different library configurations are provided for different Salvo distributions and to enable the user to minimize the Salvo kernel s footprint See the Libraries chapter of the Sa vo User Manual for more information on library configurations Because PICmicro MCUs do not have a general purpose stack the Salvo source code must be properly configured via the appropriate configuration parameters The Salvo libraries for HI TECH s PICC 18 C compiler are pr
3. The RTOS that runs in tiny places Features RM PICC18 Salvo Compiler Reference Manual HI TECH PICC 18 Reference Manual Table 1 illustrates important features of Salvo s port to HI TECH s PICC 18 C compiler general Salvo Lite LE amp Pro available distributions for Microchip PICmicro MCUs supported targets PIC18 PlCmicro MCUs header file s DOMCIOLESS h other target specific file s project subdirectory name s SYSF salvocfg h target specific header file required oe compiler auto detected yes libraries salvo lib directory htpiccl18 context switching meed label based via OSCtxSw label _OSLabel required yes size of auto variables and function parameters in tasks ATES a memory memory models supported small and large interrupts GIEL and or GIEH bits Controlled controlled via via OSPIC18_INTERRUPT_MASK configuration option interrupt status preserved in a no critical sections interrupts disabled on entry and method used enabled on exit of critical sections nesting limit no nesting permitted alternate methods possible yes debugging source level debugging only in source code builds compiler bitfield packing support yes printf p support yes no va_arg support yes Table 1 Features of Salvo Port to HI TECH s PICC 18 C Compiler The RTOS that runs in tiny places Reference Manual Compiler Optimizations Incompatible Optimizations Li
4. call an event service for a different event type only from the background one solution is to place the required foreground call inside an interrupt handler with a conditional that prevents it from ever happening e g pragma interrupt_level 0 void interrupt IntVector void real code is here dummy to satisfy call graph if 0 12 RM PICC18 Salvo Compiler Reference Manual HI TECH PICC 18 The RTOS that runs in tiny places Reference Manual Interrupt Control OSSignalBinSem OSECBP 1 This creates a call graph acceptable to HI TECH s PICC 18 C compiler and allows a successful compile and execution Interestingly the optimizer will remove the call from the final application The PIC18 architecture supports two distinct priority levels When enabled two separate global interrupt enable bits GIEH and GIEL are used to control high and low priority interrupts respectively Interrupts are automatically disabled within Salvo s critical sections By default both GIEH and GIEL are reset i e made 0 during critical sections This is controlled by Salvo s OSPIC18_INTERRUPT_MASK configuration option default value OxC0 Salvo Pro users can reconfigure the way in which interrupts are disabled during critical sections by redefining OSPIC18_INTERRUPT_MASK in the project s salvocfg h For example if Salvo services e g OSTimer are called only from low priority interrupt
5. called from mainline code i e it can only have a single callgraph A wrapper function might look like this RM PICC18 Salvo Compiler Reference Manual HI TECH PICC 18 11 Sm dV 0 Reference Manual OSSignalBinSem_Wrapper OStypeEcbP ecbP OSProtect OSSignalBinSem ecbP OSUnprotect and a wrapper macro might look like this define OSSignalBinSem_Wrapper ecbP do OSProtect OSSignalBinSem ecbP OSUnprotect while 0 Example Mixed Signaling of Multiple Event Types The library variants affect all event services equally that is an f variant library expects all applicable event services to be called from the foreground i e from within interrupts If you wish to call some services from the background and others from the foreground you ll have to use the a variant library as explained above A complication arises when you need an a variant library for a particular event type and you also are using additional event types In this case each instance of an applicable event service in use must be called from the foreground If it s not called from the foreground the compiler issue this error message Error file function _OSSignalBinSem is not called from specified interrupt level Exit status 1 However it need not be called from the background If you have the opposite situation e g you are using an a variant library for one type of event and you need to
6. in your code The interrupt_level Pragma When using the a variant libraries each instance of an applicable service in use must be called from the foreground i e from an interrupt Also PICC 18 s interrupt_level pragma must be set to 0 and placed immediately ahead of the application s interrupt routine like this pragma interrupt_level 07 void interrupt IntVector void OSStartTask TASK_P Listing 5 Setting the HI TECH PICC 18 interrupt_level Pragma for an ISR when Using a variant Libraries PICC 18 requires this in order to manage the parameter overlay areas for functions located on multiple call graphs Note This pragma has no effect if there aren t any functions located on multiple call graphs Therefore it s OK to add it to any application compiled with PICC 18 Example Foreground Signaling of One Event Type In a library build if you were to move a call to oSSignalBinSem from a Salvo task 1 e from the background to an interrupt handler i e to the foreground without changing the library variant you d find that the application crashes from a stack overflow almost immediately This is because the default interrupt control in OSSignalBinSem 1s incompatible with being placed inside an interrupt To circumvent this you must change RM PICC18 Salvo Compiler Reference Manual HI TECH PICC 18 The RTOS that runs in tiny places Reference Manual OSLIBRARY_VARIANT to osF and link an f var
7. Reference Manual 750 Naples Street San Francisco CA 94112 415 584 6360 htto www pumpkininc com Salvo Compiler Reference Manual HI TECH PICC 18 J Salvo The RTOS that runs in tiny places Copyright 2003 Pumpkin Inc last updated on Jan 6 2004 All trademarks mentioned herein are properties of their respective companies Introduction This manual is intended for Salvo users who are targeting Microchip http www microchip com PIC18 PICmicro MCUs with HI TECH s http www htsoft com PICC 18 C compiler Related Documents The following Salvo documents should be used in conjunction with this manual when building Salvo applications with HI TECH s PICC 18 C compiler Salvo User Manual Application Note AN 1 obsolete Application Note AN 3 Application Note AN 4 obsolete Application Note AN 9 Application Note AN 17 Application Note AN 26 Note PICC 18 users are strongly advised to upgrade to Microchip s MPLAB IDE v6 30 Use AN 26 in place of AN 7 and AN 4 Example Projects Example Salvo projects for use with HI TECH s PICC 18 C compiler and the Microchip MPLAB v5 and v6 IDEs can be found in the salvo ex exl sysf salvo tut tul sysf salvo tut tu2 sysf salvo tut tu3 sysf salvo tut tu4 sysf salvo tut tu5 sysf salvo tut tu6 sysf directories of every Salvo for Microchip PICmicro MCUs distribution 2 RM PICC18 Salvo Compiler Reference Manual HI TECH PICC 18
8. braries Nomenclature Type Target None of HI TECH s PICC 18 C compiler s optimizations are known to be incompatible with Salvo The Salvo libraries for HI TECH s PICC 18 C compiler follow the naming convention shown in Figure 1 It is similar to that used by HI TECH for the standard PICC 18 libraries sfp82sab lib variant a fns called from anywhere Salvo library b fns called from background only f fns called from foreground only not applicable configuration type multitasking with delays and events f freeware multitasking with delays I standard PICC 18 300 multitasking with events LFSR amp pointer size multitasking only multitasking with delays and events tasks can wait with timeouts 0 no LFSR 16 bit ROM pointers memory model no LFSR 24 bit ROM pointers I large lt 2MB address space LFSR 16 bit ROM pointers s small lt 64KB address space LFSR 24 bit ROM pointers LFSR 16 bit ROM pointers errata changes LFSR 24 bit ROM pointers errata changes Figure 1 Salvo Library Nomenclature HI TECH s PICC 18 C Compiler NOWONDM Salvo Lite distributions contain freeware libraries All other Salvo distributions contain standard libraries See the Libraries chapter of the Sa vo User Manual for more information on library types Each library is intended for one or more specific processors Table 2 lists the correct library for each PICmicro MCU RM PICC18 Salvo Compile
9. compiled limits max number of tasks 3 max number of events 5 max number of event flags 1 max number of message i queues target specific settings delay sizes 8 bits idling hook enabled interrupt enable bits during critical sections GIEH GIEL 0 interrupt level 0 message pointers can point to ROM or RAM Salvo objects persistent system tick counter available 32 bits task priorities enabled watchdog timer cleared in OSSched Table 4 Build Settings and Overrides for Salvo Libraries for HI TECH s PICC 18 C Compiler Note Because the persistent bank qualifier is used to build these libraries oSTnit must be used in all applications that use RM PICC18 Salvo Compiler Reference Manual HI TECH PICC 18 7 The RTOS that runs in tiny places Available Libraries Reference Manual these libraries Without it Salvo s variables will be uninitialized with unpredictable results Note PIC18 Salvo libraries are configured for 16 bit pointers PICC 18 s default pointer type and therefore message pointers can point to RAM and ROM Note The compiled limits for tasks events etc in Salvo libraries can be overridden to be less all Salvo distributions or more all Salvo distributions except Salvo Lite than the library default See the Libraries chapter of the Salvo User Manual for more information There are 360 Salvo libraries for HI TECH s PICC 18 C compiler Each Salvo for Microchi
10. iant library e g sfp42Caf 1lib note the f for foreground in the variant field in order to properly support event service calls in the foreground Example Foreground and Background Signaling of One Event Type If we call oSSignalBinSem from a task and from within an interrupt handler without addressing the callgraph issues the compiler issues an error message Error file function _OSSignalBinSem appears in multiple call graphs rooted at intlevelO and _main Exit status 1 To resolve this add the interrupt_level 0 pragma to your interrupt handler see Listing 5 above and use the a variant library after setting OSLIBRARY_TYPE to OSA OSProtect and OSUnprotect HI TECH s PICC 18 C compiler requires that when a function is contained in multiple callgraphs interrupts must be disabled around that function to prevent corruption of parameters and or return values Therefore you must call osProtect immediately before and OSUnprotect immediately after all background instances of every Salvo service that is called from both the background and foreground levels e g void TaskN void OSProtect OSSignalBinSem SEM_P OSUnprotect pragma interrupt_level 0 void interrupt IntVector void OSSignalBinSem SEM_P Tip Wrapping osprotect the affected Salvo service and OSUnprotect within another function can make your code more legible The wrapper may only be
11. ll banks Salvo Pro build differs slightly from Salvo Lite build due to configuration see tutorial s salvocfg h Salvo always uses level 0 OSSignalBinSem like many other user services disables interrupts on entry and blindly re enables them on exit The re enabling of interrupts if placed inside a PICmicro interrupt routine causes problems OSSignalBinSem in the f and a variant libraries control interrupts differently See PICC 18 manual for more information 14 RM PICC18 Salvo Compiler Reference Manual HI TECH PICC 18
12. ovided in different variants as shown in Table 3 If your application does not call any Salvo services from within interrupts use the b variant If you wish to these services exclusively from within interrupts use the f variant If you wish to do this from both inside and outside of interrupts use the a variant In each case you must call the services that you use from the correct place in your application or either the linker will generate an error or your application will fail during runtime RM PICC18 Salvo Compiler Reference Manual HI TECH PICC 18 The RTOS that runs in tiny places Build Settings Reference Manual variant code description Applicable services can be called from anywhere i e from the Ta foreground and the background simultaneously b OSB Applicable services may only be called from the background default OSF Applicable services may only be called from the foreground OSNONE Library has no variants Table 3 Variants for Salvo Libraries HI TECH s PICC 18 C Compiler See the OSCALL_oSxyZ configuration parameters for more information on calling Salvo services from interrupts See Multiple Callgraph Issues below for more information on using library variants Salvo s libraries for HI TECH s PICC 18 C compiler are built using the default settings outlined in the Libraries chapter of the Salvo User Manual Target specific settings and overrides are listed in Table 4
13. p PICmicro MCUs distribution contains the Salvo libraries of the lesser distributions beneath it salvocfg h Examples Below are examples of salvocfg h project configuration files for different Salvo for PICmicro MCUs distributions targeting the PIC18C452 Note When overriding the default number of tasks events etc in a Salvo library build ostasKs and OSEVENTS respectively must also be defined in the project s salvocfg h If left undefined the default values see Table 4 will be used Salvo Lite Library Build define OSUSE_LIBRARY TRUE define OSLIBRARY_TYPE OSF define OSLIBRARY_CONFIG OSA define OSLIBRARY_VARIANT OSB Listing 2 Example salvocfg h for Library Build Using sfp80lab lib RM PICC18 Salvo Compiler Reference Manual HI TECH PICC 18 The RTOS that runs in tiny places Salvo LE amp Pro Library Build Reference Manual define OSUSE_LIBRARY define OSLIBRARY_TYPE define OSLIBRARY_CONFIG define OSLIBRARY VARIANT TRUE OSL OSA OSB Listing 3 Example salvocfg h for Library Build Using Salvo Pro Source Code Build define OSE slp80lab lib NABLE_IDLING_HOOK ENABLE SEMAPHORES define OS define OS EVENTS define OS OC_ALL define OST Listing 4 Performance Memory Usage tutorial memory usage tullite tu2lite tu3lite tu4lite tud5lite tu lite tu6pro ASKS
14. r Reference Manual HI TECH PICC 18 B savo Reference Manual The RTOS that runs in tiny places target code processor s all PIC18 PICmicro MCUs 80s 801 Sis Bilis Recommended only for 18C242 18C252 18C442 180452 all PIC18 PlCmicro MCUs except 18C242 180252 18C442 18C452 826 821 838 83Ls 18F252 18F258 18F452 18F458 Recommended for all other PIC18 PlCmicro MCUs 86s 861 87s 871 7 18F252 18F258 18F452 18F458 Table 2 Processors for Salvo Libraries HI TECH s PICC 18 C Compiler Note The p80s p801 p81s p811 Salvo libraries are for those early PIC18 PICmicro MCUs that do not support the LFsR instruction correctly e g 18C242 18C252 18C442 18C452 All later devices in the family support this instruction correctly On targets that support LFsR correctly using libraries with LFSR support will result in smaller and faster code Verifying the Target Code You can verify that you have chosen the right Salvo library by observing the PICC 18 C compiler s actions Open the project s map file and look towards the end of the Linker command line entry There you will see which PICC 18 library was used to build your application Use the same target code for your Salvo library For example Listing 1 shows the linker command line entry for a PICC 18 project built for the PIC18F6220 C HTSOFT PIC18 LIB pic821 c lib Listing 1 Example Linker Command Line for PIC18F6220 from map file
15. s then a value of 0x40 for OSPIC18_INTERRUPT_MASK ensures that only low priority interrupts are disabled during a Salvo critical section In this configuration high priority interrupts will therefore be unaffected by Salvo This is especially useful when high rate interrupts are present This is done automatically through the HI_TECH_C and _PIC18 symbols defined by the compiler The lack of an addressable stack severely limits the scope of alternate methods As of PICC 18 v8 00 4 Specifically the PIC18FXX2 Rev B3 and PICI8FXX8 Rev B4 parts Consult PICC 18 readme files for more information 3 See Microchip s PIC18CXX2 Frrata Note that the PICC 18 library is automatically added to the linker command line The Salvo library must be added manually by the user as part of setting up the project A library may have no variants if the target processor does not support interrupts Each event flag has RAM allocated to its own event flag control block RM PICC18 Salvo Compiler Reference Manual HI TECH PICC 18 13 we AIVO Reference Manual Each message queue has RAM allocated to its own message queue control block Argument for PICC 18 s pragma interrupt_level for those services that can be called from within an ISR By making Salvo s variables persistent the PICC 18 compiler is able to omit some initialization code and thus reduce ROM requirements 2 Salvo v3 2 0 with PICC 18 v8 20PL4 In bytes In bytes a
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