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Enabling Low Power Modes with the Z8 Encore!

1. 1 Measurements are not in cumulative order but instead are individual measurements in condition and mode The values in this table were measured using a microammeter To determine more exact values use a nano ammeter ANO0315302 051 1 Page 6 of 16 Enabling Low Power Modes with the Z8 Encore XP F1680 Series MCU Application Note Z AnEITXYS C Table 2 Current and Power Consumption in NORMAL HALT and STOP Modes Continued Current Consumption Mode mA Power mW Condition 3 0V 2 667 8 001 Fsysc_k 11 0592MHz IPO all peripherals enabled including VBO WDT TO and T1 2 421 7 264 Fsyscik 11 0592MHz IPO WDT TO and T1 enabled all other peripherals disabled HALT 2 419 7 257 Fsysc_k 11 0592 MHz IPO TO and T1 enabled all other peripherals disabled 2 367 7 101 Fsysc_k 11 0592 MHz IPO WDT enabled all other peripherals disabled 2 365 7 095 Fsysc_k 11 0592 MHz IPO all peripherals disabled 0 006 0 018 WDT TO and T1 enabled all other peripherals disabled STOP 0 004 0 012 TO and T1 enabled all other peripherals disabled 0 002 0 006 WDT enabled all other peripherals disabled 0 001 0 003 All peripherals disabled Notes The term peripherals refers to the Op Amps LVD VBD Temp Sensor Comp 0 and Comp 1 Measurements are not in cumulative order but instead are individual measurements in condition and mode The values in this table were measured using a microammete
2. 7 PWRCTLO PWRCTLO OC 1C OC 1c OC 1 OC 1C EI LO LO L1 L1 L2 L2 L1 L1 0x18 0xCO use IPO to Drive System Clock 0x00 LPO VBO TEMP Ox9B LPO VBO TEMP COMP COMP are enabled are disabled 0x00 Set up TO amp T1 Timers 0x00 Driven by external 32Khz CRYSTAL 0x39 0x39 0x00 0x00 0x80 0x80 for x 0 x lt 100 x for i 0 1 lt OxFFFF i PCOUT PCOUT PAOUT PAOUT asm WDT asm STOP Put the device Uncomment this asm HALT Put the device Uncomment this while 1 in STOP mode for S TOP mode in HAI LT mode for HALT mode ANO0315302 0511 Page 15 of 16 Enabling Low Power Modes with the Z8 Encore XP F1680 Series MCU Application Note Zilc En AnEITXYS Company Customer Support To share comments get your technical questions answered or report issues you may be experiencing with our products please visit Zilog s Technical Support page at http support zilog com To learn more about this product find additional documentation or to discover other fac ets about Zilog product offerings please visit the Zilog Knowledge Base at http zilog com kb or consider participating in the Zilog Forum at http zilog com forum This publication is subject to replacement by a later edition To determine whether a
3. Application Note Zilog Embedded in Life Enabling Low Power Modes with the AnEXIXYS Company Z8 Encore XP F1680 Series MCU AN031302 0511 Abstract This application note discusses methods that can be used to enable low power modes on the Z8 Encore XP F1680 Series MCU It describes how to employ NORMAL HALT and STOP modes to achieve varying degrees of low power consumption by enabling disabling peripherals for additional power savings gt Note The source code files associated with this application note AN0313 SC01 have been tested with ZDS HI version 4 11 1 Features The Z8 Encore XP F1680 Series MCU offers the following power saving features Low power modes that can be set by the user A power control register that enables users to turn peripherals ON and OFF when not in use e A wide operating voltage range of 1 8V to 3 6V nternal Precision Oscillator IPO with a wide range of selectable system clock fre quencies Execution out of Program RAM For more information refer to the ZIGFMC Series Product Specification PS0250 avail able for download at http www zilog com Discussion Zilog s Z8 Encore XP F1680 Series MCU family is based on the advanced 8 bit eZ8 CPU core This microcontroller is optimized for low power applications and supports low volt age operation 1 8 V 3 6 V with extremely low NORMAL HALT and STOP mode cur rents The F1680 offers an assortment of speed and low power options including
4. F PRAM Enabled LASH OPTION2 OxFF Default user flash option2 nj Next use the IPO by placing 0xCO0 into OSCCTLI to serve as the clock source as fol lows OSCCTLO OSCCTL1 0x8A0 Use Internal Clock F 11 0592 MHZ 0xCO0 use IPO to Drive System Clock Disable the Timers if they are not required in your design and instead use the peripheral timer clock source ADC and IC can also be disabled to reduce power consumption by setting ADCCTLO 0x00 and I2CCTL 0x00 The control registers that govern the other peripherals can be used to attain additional power savings and power in the periph eral block can be disabled via the Power Control Register as shown below PWRCTLO OxFF TRAM LVD VBO TEMP COMPO COMP1 are turned off Setting or clearing each bit of the Power Control Register enables or disables power in the peripheral block PWRCTLO can be initialized in any part of the source code To execute in Program RAM PRAM during NORMAL Mode the determination was to insert the pragma PRAM statement above the void main void statement as shown pragma PRAM Void main void Example 1 below turns the LED ON and OFF in PORT C and goes into STOP HALT mode after 50 cycles Example 1 Blinker Program with STOP Mode for x 0 x lt 100 x for 1 0 i lt OxFFFF i PCOUT PCOUT PCOUT 0x00 asm STOP while 1 ANO031302 051 1 Page 8 of 16 Enabling Low Power Modes with the Z8 Enc
5. SE The information contained within this document has been verified according to the general principles of electrical and mechanical engineering Z8 Z8 Encore Z8 Encore XP and ZMOTION are trademarks or registered trademarks of Zilog Inc All other product or service names are the property of their respective owners ANO031302 0511 Page 16 of 16
6. chdog Timer WDT logic continues operating e fenabled the 32kHz secondary oscillator continues operating Jfenabled for operation in STOP Mode the Timer logic continues to operate with a 32kHz secondary oscillator as the Timer clock source If enabled for operation in STOP Mode by the associated Flash Option Bit the VBO protection circuit continues operating The low voltage detection circuit continues to operate if it is enabled by the Power Control Register e The Low Power Operational Amplifier and comparator continue to operate if they are enabled by the Power Control Register e All other on chip peripherals are idle and powered down When the device is in STOP Mode a Stop Mode Recovery is initiated by each of the fol lowing A Watchdog Timer time out e A GPIO Port input pin transition on an enabled Stop Mode Recovery source e An interrupt from a timer or comparator enabled for STOP Mode operation The low voltage detection circuitry on the F1680 device features the following The low voltage detection threshold level is user defined The device generates an interrupt when the supply voltage drops below a user defined level gt Note If the system does not have a process to execute the eZ8 CPU should be placed into STOP Mode and await any transition in the Stop Mode Recovery assignment pin to bring it out of STOP Mode ANO031302 051 1 Page 5 of 16 Enabling Low Power Modes with the Z8 Encore XP F1680 Serie
7. ct Specification PS0250 Z8 Encore XP F1680 28 pin Development Kit User Manual UM0203 ANO0315302 051 1 Page 12 of 16 Enabling Low Power Modes with the Z8 Encore XP F1680 Series MCU Application Note zilog Embedded in Life AnEITXYS Company Appendix A Z8 Encore XP F1680 Block Diagram Figure 7 shows the architecture of the Z8 Encore XP F1680 MCU complete with periph eral blocks Pc Figure 6 Z8 Encore XP F1680 Block Diagram AN031302 051 1 Page 13 of 16 Enabling Low Power Modes with the Z8 Encore XP F1680 Series MCU Application Note Zilog Embedded in Life AnElIXYS Company Appendix B Low Power Modes ED at PORTC Blinker Program wit Source Code h Low Power Modes Ck ck ck ck ck ck Ck KKK KKK KKK KKK ck ck ck KK KKK KK KKK KKK KKK KKK ck kk KKK kk ko ck Sk ko kc Sk ck kc k ko k ko ko kc KKK This is compiled using ZDSII Z8 Copyright C 1999 2008 by Zilog ine Zilog employee or a licensed consultant been verified to the fullest users are cautioned to authenticate th Encore 4 ALL RIGHTS RES The source code in this file was written by an authorized xtent possible Permission use this code is granted on a royalty free basis cod 11 0 ERVED The source code has to However contained herein ox xo F HF X Zilog DOES NOT GUARANTEE THE VERACITY OF THE SOFTWARE Ck ck ck ck ck ck C
8. ed the internal RC oscillator of the WDT continues to operate Jfenabled the WDT continues to operate e Ifenabled the 32kHz secondary oscillator for Timers continues to operate All other on chip peripherals continue to operate The eZ8 CPU can be brought out of HALT mode by any of the following operations Timer timeout Interrupt or Reset Interrupt if enabled e Watchdog e Power On Reset e Voltage Brownout Reset e External RESET pin assertion gt Note You can place the device into HALT mode if the system does not have a process to exe cute however the peripherals can continue to operate and wait for an interrupt to bring them out of HALT mode STOP Mode Executing the eZ8 CPU s STOP instruction places the device into STOP Mode In STOP Mode the operating characteristics are ANO031302 051 1 Page 4 of 16 Enabling Low Power Modes with the Z8 Encore XP F1680 Series MCU Application Note Zilog imbedded in AnEITXYS Company e The primary crystal oscillator and the internal precision oscillator are stopped XIN and XOUT if previously enabled are disabled and if previously enabled for port function PAO PA1 reverts to the states programmed by the GPIO registers The system clock is stopped The eZ8 CPU is stopped The program counter PC stops incrementing The Watchdog Timer s internal RC oscillator continues operating if enabled by the Oscillator Control Register If enabled the Wat
9. k KKK KKK KKK KK KKK KKK KKK KK KKK KKK KKK KKK ck kk KKK kk ko kk kk Sk Ck kc k KKK k ck KKK include ez8 h FLASH OPTION1 OxF7 FLASH OPTION2 OxFF pragma PRAM void main void WDT ON Everything OFF unsigned int delay 5000 unsigned int x i DI WDTH 0x55 WDT Unlock Sequence WDTH OxAA WDTH OxFF WDT Timer WDTL OxFF Max OxFFFF 6 55 sec LEDEN 0x00 LEDLVLH 0x00 LEDLVLL 0x00 PADD 0x04 PA as Output MODE PAAF 0x00 PAOC 0x00 PAHDE 0x00 PAPUE 0x00 PASMRE 0x00 PASMRE 0x040 Mode Recovery For HALT mode PAOUT OxFF PA Data FFH PBDD 0x00 PBAF 0x00 PB as Output MODI LH PBOC 0x00 PBHDE 0x00 PBPUE 0x00 PBSMRE 0x00 PBOUT OxFF PB Data FFH ITO amp T1 enable amp Running on Stop Mode Any logic transition on this port during STOP mode initiates Stop Reset assertion initiate recovery ANO0315302 0511 Page 14 of 16 Enabling Low Power Modes with the Z8 Encore XP F1680 Series MCU Application Note Zilog Embedded in Life AnEITXYS Company PCDD 0x00 PC as Output MODE PCAF 0x00 PCOC 0x00 PCPUE 0x00 PCHDE 0x00 PCSMRE 0x00 PCOUT OxFF PC Data FFH OSCCTLO OxE7 Unlock sequence OSCCTLO 0x18 OSCCTLO 0x80 OSCCTLO 0x80 0x20 while delay OSCCTLI OSCCTLI OSCCTLI OxE
10. later edition exists please visit the Zilog website at http www zilog com AN Warning DO NOT USE THIS PRODUCT IN LIFE SUPPORT SYSTEMS LIFE SUPPORT POLICY ZILOG S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS PRIOR WRITTEN APPROVAL OF THE PRESIDENT AND GENERAL COUNSEL OF ZILOG CORPORATION As used herein Life support devices or systems are devices which a are intended for surgical implant into the body or b support or sustain life and whose failure to perform when properly used in accordance with instructions for use provided in the labeling can be reasonably expected to result in a significant injury to the user A critical component is any component in a life support device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or system or to affect its safety or effectiveness Document Disclaimer 2011 Zilog Inc All rights reserved Information in this publication concerning the devices applications or technology described is intended to suggest possible uses and may be superseded ZILOG INC DOES NOT ASSUME LIABILITY FOR OR PROVIDE A REPRESENTATION OF ACCURACY OF THE INFORMATION DEVICES OR TECHNOLOGY DESCRIBED IN THIS DOCUMENT ZILOG ALSO DOES NOT ASSUME LIABILITY FOR INTELLECTUAL PROPERTY INFRINGEMENT RELATED IN ANY MANNER TO USE OF INFORMATION DEVICES OR TECHNOLOGY DESCRIBED HEREIN OR OTHERWI
11. ol and is meant to store the interrupt service routines of high frequency interrupts Because interrupts bring the CPU out of low power ANO031302 051 1 Page 2 of 16 Enabling Low Power Modes with the Z8 Encore XP F1680 Series MCU Application Note mode it is important to ensure that interrupts that occur very often use as low a current as possible Program RAM based handling of high frequency interrupts provides power sav ings by keeping the Flash block disabled It is optimized for low current operation and can be easily boot strapped with interrupt code at power up Power Control Register Each bit in the register listed in Table 1 disables a peripheral block by removing power from the block the default state of the low power operational amplifier is OFF To use the low power operational amplifier clear the TRAM bit by turning it ON The TRAM bit enables the amplifier in STOP Mode if the amplifier is not required in STOP Mode dis able it Failure of the op amp to perform could result in STOP Mode currents greater than specified AN Caution Clearing the TRAM bit could interfere with normal ADC measurements on the LPO out put ANAO Table 1 Power Control Register 0 PWRCTLO Bits 7 6 5 4 3 2 1 0 Field TRAM Reserved LVD VBO TEMP Reserved COMPO COMP1 Reset 1 0 0 0 0 0 0 R W R W R W R W R W R W R W R W ADDR F80H Bit Description 7 TRAM 0 Low Power Ope
12. ore XP F1680 Series MCU Application Note Zilog Embedded in Life AnEITXYS Company The asm STOP command places the device into STOP Mode The device can be brought out of STOP Mode by means of a Stop Mode Recovery Configure this Stop Mode Recovery by tying the GPIO interrupt at pin PA2 Any logic transition at pin PA2 can bring the device out of STOP Mode as shown by the following code and Figure 2 PADD PAAF PAOC PAHDE PAPUE R PASMRE VCC_30V B 0x04 0x00 0x00 0x00 0x04 0x04 R1 SW1 RECOVERY 100K R2 100 Figure 2 Recovery from STOP Mode at Pin PA2 The Blinker program used in Example 1 can also be used to place the F1680 device into HALT mode as shown in Example 2 Example 2 Blinker Program with HALT mode for x 0 x lt 100 x for i 0 i lt OxFFFF i PCOUT PCOUT PCOUT 0x00 asm HALT while 1 The asm HALT command places the device into HALT mode The device can be brought out of HALT Mode by a reset or a Stop Mode Recovery and by using a RESET assertion as shown in Figure 3 ANO0315302 0511 Page 9 of 16 Enabling Low Power Modes with the Z8 Encore XP F1680 Series MCU Application Note Zilog Embedded in Life AnEITXYS Company R1 SW1 1 VCC_30V O GND RESET 100K PDO Figure 3 Recovery from HALT Mode To review the entire codeset for the with low power mode Blinker program see Appendix B on page 14 Required Eq
13. r To determine more exact values use a nano ammeter Hardware Architecture To minimize power consumption when the system is not in use the F1680 MCU is equipped with a low power modes option with which the user can place the MCU into STOP and HALT modes The capability to control peripherals can add further power sav ings The Power Control Register allows the user to disable or enable power in unused peripherals for additional power reduction For a visual representation of the op amp LVD VBO temperature sensor comparators and peripherals that the Power Control Reg ister can control see the architectural diagram in Appendix A on page 13 Software Implementation The reference design discussed in this application note uses ZDSII v4 11 0 and the Z8 Encore XP F1680 Development Kit to simulate the STOP and HALT low power modes while controlling the peripherals with the Power Control Register In this design the objective is to implement these low power modes using the blinker program First configure the LVD VBO to be OFF during STOP and HALT modes The following code segment demonstrates a placement of the value OxF 7 into Flash Option Register 1 to turn off VBO in Stop Mode the PRAM is used as Program RAM include ez8 h ANO031302 0511 Page 7 of 16 Enabling Low Power Modes with the Z8 Encore XP F1680 Series MCU Application Note Zilog Embedded in Life AnElIXYS Company nj LASH_OPTION1 OxF7 VBO AO OF
14. rational Amplifier is enabled also applicable to STOP Mode 1 Low Power Operational Amplifier is disabled 6 5 Reserved LVD VBO Low Voltage Detection Voltage Brownout Detector Disable 0 LVD VBO Enabled 1 LVD VBO Disabled The LVD and VBO circuits are enabled or disabled separately to minimize power consumption in low power modes The LVD is controlled only by the LVD VBO bit in all modes The VBO is set by the LVD VBO bit as well as the VBO_AO bit of Flash Option bits at Program Memory Address 0000H 3 TEMP Temperature Sensor Disable 0 Temperature Sensor Enabled 1 Temperature Sensor Disabled 2 Reserved 1 If peripherals are not in use the user can turn off the peripheral bit in all modes to reduce power consumption ANO031302 0511 Page 3 of 16 Enabling Low Power Modes with the Z8 Encore XP F1680 Series MCU Application Note zilog Embedded in AnEITXYS Company 1 COMPO Comparator 0 Disable 0 Comparator 0 is Enabled also applicable to STOP Mode 1 Comparator 0 is Disabled 0 COMP1 Comparator 1 Disable 0 Comparator 1 is Enabled also applicable to STOP Mode 1 Comparator 1 is Disabled HALT Mode Executing the HALT instruction places the device into HALT mode which manifests the following operating characteristics The primary oscillator is enabled and continues to operate The system clock is enabled and continues to operate The program counter PC stops incrementing Jfenabl
15. s MCU Application Note Z AnEITXYS Company Table 2 Current and Power Consumption in NORMAL HALT and STOP Modes Current Consumption Mode mA Power mW Condition 3 0 V 5 792 17 376 Fsvscik2 11 0592MHz IPO PRAM D all peripherals enabled 5 783 17 349 Fsvscik2 11 0592 MHz IPO PRAM D LPOA disabled all other peripherals enabled 5 772 17 316 Fsyscik 11 0592MHz IPO PRAM D LVD VBO disabled a all other peripherals enabled xecution from Flash 2 937 17 211 Fsysc_k 11 0592 MHz IPO PRAM D Temperature Sensor disabled all other peripherals enabled 5 604 16 812 Fsvscik2 11 0592 MHz IPO PRAM D Comparator disabled all other peripherals enabled 5 542 16 626 Fsysc_k 11 0592MHz IPO PRAM D all peripherals disabled 3 628 10 884 Fsysc_k 11 0592MHz IPO PRAM E all peripherals enabled 3 621 10 863 Fsysc_ik 11 0592 MHz IPO PRAM E LPOA disabled all other peripherals enabled 3 607 10 821 Fsysc_k 11 0592MHz IPO PRAM E LVD VBO disabled NORMAL all other peripherals enabled Execution from PRAM 3 581 10 743 FsyscLk 11 0592 MHz IPO PRAM E Temperature Sensor disabled all other peripherals enabled 3 462 10 386 Fsysc_k 11 0592 MHz IPO PRAM E Comparator disabled all other peripherals enabled 3 406 10 218 FsyscLk 11 0592 MHz IPO PRAM E all peripherals Notes disabled e The term peripherals refers to the Op Amps LVD VBD Temp Sensor Comp 0 and Comp
16. the option to disable and enable a number of peripherals A customized platform featuring a universal printed circuit board is used to obtain current measurements for this low power exercise All factors that could have had an influence on total current consumption were removed from this customized board however a 32KHz ANO031302 051 1 Page 1 of 16 Enabling Low Power Modes with the Z8 Encore XP F1680 Series MCU Application Note Embedded in Life AnElIXYS Company external crystal oscillator was installed to provide the lowest current consumption in STOP MODE Figure 1 shows the customized Z8 Encore XP F1680 Series board and Universal PCB AITTTLELI 5 E M B 58 NM 9 8M M S M 3S SN i i _ e E EEE jj f 1 z L f TM irii Sont EE C x 171 TESTI Lad Figure 1 The Customized Z8 Encore XP F1680 Series Board and Universal PCB Normal Mode The F1680 Series MCU operates in default MCU configuration the peripheral blocks are enabled except for a low power operational amplifier which is disabled by default For default values and op amp configurations please see Zilog s companion document the Z8 Encore XP F1680 Series Product Specification PS0250 Program RAM The Z8 Encore XP F1680 Series devices contain up to 1 KB of on chip Program RAM This Program RAM is mapped in the Program Memory address space beyond the on chip Flash memory It is entirely under user contr
17. uipment The equipment listed below is used to build the Blinker application 1 F1680 Series Development Kit featuring the F1680 MCU 2 ZDSII Z8 Encore 4 11 0 3 Multimeter 4 Power Supply Setup Figures 4 and 5 show a simple block diagram and an actual image of the Blinker applica tion setup AMMETER mA DC SOURCE Z8 Encore XP 3 0V F1680 Figure 4 Blinker Application Setup Block Diagram ANO031302 0511 Page 10 of 16 Enabling Low Power Modes with the Z8 Encore XP F1680 Series MCU Application Note Zilog Embedded in Life AnEITXYS Company Figure 5 Blinker Application Setup Actual Results Each mode of operation results in a significant reduction in power consumption See on page 6 for the measurement results showing current and power usage under different modes and conditions Summary This application note provides a blueprint for utilizing the low power features of the Z8 Encore XP F1680 Series MCU A simple hardware architecture and a simple Blinker pro gram enable different low power mode possibilities The Blinker software is modular and easy to customize for any low power application ANO0315302 051 1 Page 11 of 16 Enabling Low Power Modes with the Z8 Encore XP F1680 Series MCU Application Note Zilog Embedded in Life AnEITXYS Company References The following documents associated with the Z8 Encore XP F1680 device are available on www zilog com Z8 Encore XP F1680 Series Produ

Enabling Low Power Modes with the Z8 Encore!

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