STM8 in-application programming (IAP) using a customized user
Contents
1. set back code section to default placement pragma section 5 3 Finishing and checking the configuration By using either one of the above processes Creating a segment in the STVD project or Creating a memory segment in the Cosmic linker file the FlashWrite and FlashErase functions are compiled and linked for RAM execution in the section FLASH CODE but their code is placed in the Flash memory after the text and init sections This can be seen in the generated map file Example of final map file Segments start 00008080 end 00008500 length 1152 segment text start 00000000 end 00000000 length 0 segment bsct start 00000000 end 00000003 length 3 segment ubsct start 00000003 end 00000098 length 149 segment RAM start 00000098 end 00000098 length 0 segment share start 00000100 end 00000100 length 0 segment data start 00000100 end 00000100 length 0 segment bss start 00000100 end 000001F0 length 240 segment FLASH CODE initialized start 00008510 end 00008600 length 240 segment FLASH CODE from start 00008000 end 00008080 length 128 segment const start 00008500 end 00008510 length 16 segment init The map file shows the location of the FLASH CODE sections One section is for storage in the Flash it is stored in the map file marked from The other section is for execution it is stored in the map file marked initialized Finally the microcontroller firmware mu2. Doc ID 14153 Rev 2 11 25 www BDTIC com ST User bootloader for STM8 devices AN2659 3 2 12 25 Configuring the user bootloader firmware example The provided package is configured for STM8S105xx devices with I C protocol The package can be reconfigured easily without any source code modification by modifying information in the main h files see package description The configuration file is divided into three sections see below Each section can be modified depending on requirements USER BOOTLOADER PROTOCOL PARAMETERS This section is used to select a protocol The user bootloader firmware example supports three protocols UART I C and SPI Only one protocol can be selected USER USER BOOT CODE Customisation This section is used for defining byte values acknowledge non acknowledge and identification command numbers and received data buffer structure USER BOOT CODE MEMORY PARAMETERS This section is used to describe the memory configuration of the STM8 microcontroller It is mandatory to set up some memory variables corresponding to the memory configuration of the microcontroller for example memory size block size EEPROM size and address range For more informations on these variables please refer to the appropriate device datasheet Doc ID 14153 Rev 2 ky www BDTIC com ST AN2659 Memory management for IAP 4 Memory management for IAP
3. TI AN2659 Sf Application note STM8 in application programming IAP using a customized user bootloader Introduction This application note is intended for STM8 firmware and system designers who need to implement an in application programming IAP feature in the product they are developing with the STM8 microcontroller The STM8 is an 8 bit microcontroller family with a Flash memory for storing the user program code or firmware IAP makes it possible to update the firmware in situ after the microcontroller has been embedded in the final product The advantage is that the microcontroller board can stay inside its product enclosure No mechanical intervention is needed to make the update IAP is extremely useful for distributing new firmware versions It makes it easy to add new product features and correct problems throughout the product life cycle The user bootloader firmware source code provided with this application note shows an example of how to implement IAP for the STM8 microcontroller Use this code as a reference when integrating IAP in your STM8 application It includes the following features Bootloader activated by external pin jumper on PCB Flash block programing by executable RAM code management Read while write RWW feature High level C language usage Reduced size of the code optimized code Support for multiple communication interfaces SPI FC and UART UART code compatible with ST Flash loader
4. can be found in the relevant device datasheet Activation of the built in ROM bootloader is made by programming the BL 7 0 option byte described in the option byte section of the device datasheet The bootROM bootloader checks this option byte and if it is enabled it runs its own code it waits for the host to send commands data If the BL 7 0 option byte is inactive the bootrom bootloader jumps to the user reset address 0x8000 Figure 2 Example of STM8S208xx bootloader 0x6000 La BootROM EE EE 0x8000 Flash program memory 0x02 7FFF ai17466 6 25 Doc ID 14153 Rev 2 ky www BDTIC com ST AN2659 STM8 devices with built in ROM bootloader 2 2 Adapting IAP master side to ROM bootloader protocol To be able to download firmware into the device the host and bootloader must communicate through the same protocol This bootloader protocol for STM8 devices is specified in the STM8 bootloader UMO560 user manuals available from http www st com The same protocol is used in the firmware example provided with this application note The UMO560 user manual describes all bootloader protocol properties including used interfaces timeouts command formats packet formats and error management Doc ID 14153 Rev 2 7 25 www BDTIC com ST User bootloader for STM8 devices AN2659 3 8 25 User bootloader for STM8 devices For STM8 microcontrollers which do not include a built in bootloader or wh
5. FLASH peripheral registers to their default reset values void FLASH EraseBlock u16 BlockNum FLASH_MemType_TypeDef MemType Erases a block in the program or data EEPROM memory void FLASH_EraseByte u32 Address Erases one byte in the program or data EEPROM memory void FLASH_EraseOptionByte u32 Address Erases an option byte u32 FLASH_GetBootSize void Returns the boot memory size in bytes FlagStatus FLASH_GetFlagStatus FLASH_Flag_TypeDef FLASH_FLAG Checks whether the specified Flash flag is set or not FLASH_LPMode_TypeDef FLASH_GetLowPowerMode void Returns the Flash behavior type in low power mode FLASH_ProgramTime_TypeDef FLASH_GetProgrammingTime void Returns the fixed programming time void FLASH_ITConfig FunctionalState NewState Enables or disables the Flash interrupt mode void FLASH Lock FLASH_MemType_TypeDef MemType Locks the program or data EEPROM memory void FLASH ProgramBlock u16 BlockNum FLASH_MemType_TypeDef MemType FLASH_ProgramMode_TypeDef ProgMode u8 Buffer Programs a memory block void FLASH_ProgramByte u32 Address u8 Data Programs one byte in the program or data EEPROM memory void FLASH_ProgramOptionByte u32 Address u8 Data Programs an option byte Doc ID 14153 Rev 2 ky www BDTIC com ST AN2659 Memory management for IAP Note void FLASH_ProgramWord u32 Address u32 Data Programs one word 4 bytes in the program or data EEPROM memory
6. Memory protection Flash memory protection To avoid accidental overwriting of the Flash code memory for example in the case of a firmware crash several levels of write protection are implemented in the STM8 microcontroller family After an STM8 reset write access to the Flash memory is disabled To enable it firmware must write two unlock keys in a dedicated register If the unlock keys are correct 0x56 OxAE write access to the Flash memory is enabled and it is possible to program the Flash memory using either byte word or block programming mode If the unlock keys are incorrect write access to the Flash memory is disabled until the next device reset After writing to the Flash memory it is recommended to enable write protection again by clearing a specific bit in the Flash control register to avoid accidental write A similar protection mechanism exists for the Data EEPROM memory with a specific unlock register and unlock keys OxAE 0x56 User boot code protection UBC Additional write protection exists for the programming code itself to protect the user bootloader code from being overwritten during IAP The STM8 family has a user boot code UBC area which is permanently write protected This UBC area starts from the Flash memory start address 0x8000 and its size can be changed by the UBC option byte see device reference manuals and product datasheets The boot code area also includes an interrupt vector table 0x8000 to 0
7. The ST proprietary bootloader can be used It is embedded in the ROM memory of STM8 devices with a program memory greater than 8 Kbytes In this case no code development is needed To use the proprietary bootloader enable it via the option bytes Alternatively develop a customized bootloader using for example a serial communication interface that is not supported in ST versions or in devices where the ST bootloader is not present Such a bootloader should be stored in the user boot code area UBC in the microcontroller This guarantees protection against unintentional write operations Doc ID 14153 Rev 2 5 25 www BDTIC com ST STMS devices with built in ROM bootloader AN2659 2 STM8 devices with built in ROM bootloader Most STM8 devices have an internal bootROM memory which contains an ST proprietary bootloader Consequently they already have a built in IAP implementation see UMO560 STMB8 bootloader 2 1 Implementation details The built in ROM bootloader is located in a dedicated part of the memory called the BootROM The ROM bootloader code is fixed not rewritable and is specific for each device The communication interface supported depends on the peripherals present in the given STM8 device and whether they are implemented in the ROM bootloader For example some devices support firmware download through UART LIN and CAN some devices support only UART and others only SPI Information concerning the supported interfaces
8. any intellectual property contained therein UNLESS OTHERWISE SET FORTH IN ST S TERMS AND CONDITIONS OF SALE ST DISCLAIMS ANY EXPRESS OR IMPLIED WARRANTY WITH RESPECT TO THE USE AND OR SALE OF ST PRODUCTS INCLUDING WITHOUT LIMITATION IMPLIED WARRANTIES OF MERCHANTABILITY FITNESS FOR A PARTICULAR PURPOSE AND THEIR EQUIVALENTS UNDER THE LAWS OF ANY JURISDICTION OR INFRINGEMENT OF ANY PATENT COPYRIGHT OR OTHER INTELLECTUAL PROPERTY RIGHT UNLESS EXPRESSLY APPROVED IN WRITING BY TWO AUTHORIZED ST REPRESENTATIVES ST PRODUCTS ARE NOT RECOMMENDED AUTHORIZED OR WARRANTED FOR USE IN MILITARY AIR CRAFT SPACE LIFE SAVING OR LIFE SUSTAINING APPLICATIONS NOR IN PRODUCTS OR SYSTEMS WHERE FAILURE OR MALFUNCTION MAY RESULT IN PERSONAL INJURY DEATH OR SEVERE PROPERTY OR ENVIRONMENTAL DAMAGE ST PRODUCTS WHICH ARE NOT SPECIFIED AS AUTOMOTIVE GRADE MAY ONLY BE USED IN AUTOMOTIVE APPLICATIONS AT USER S OWN RISK Resale of ST products with provisions different from the statements and or technical features set forth in this document shall immediately void any warranty granted by ST for the ST product or service described herein and shall not create or extend in any manner whatsoever any liability of ST ST and the ST logo are trademarks or registered trademarks of ST in various countries Information in this document supersedes and replaces all information previously supplied The ST logo is a registered trademark of STMicroelectronics All other nam
9. command read write erase version 4 Ifa Go command is received the user bootloader jumps to the address given in the command All commands have a specified format and must be followed by both the user bootloader and the master The command specification handles all possibilities and covers error management Doc ID 14153 Rev 2 9 25 www BDTIC com ST User bootloader for STM8 devices AN2659 10 25 Several specific processing methods must be taken into account to achieve the appropriate action in the memory using the bootloader These methods are explained in Section 4 Memory management for IAP They include Protection management Code execution from RAM depending on memory write method byte word or block programming Doc ID 14153 Rev 2 ky www BDTIC com ST AN2659 User bootloader for STM8 devices Figure 5 Bootloader flowchart Valid user reset vector IO pin grounded Init VO pin pull up Yes d User application start No Communication interface init protocol in timeout interval Received token Yes Yy Copy write block routine into RAM y Wait for command from Master lt t Yes Jump to GO address GO command to run user code Parse commands WRITE ERASE READ VERSION Y Perform command
10. data into the EEPROM buffer must execute from the RAM However during the physical programming phase which takes more time several milliseconds the code runs from the Flash while the data EEPROM memory is programmed in the background Completion of data EEPROM programming is indicated by a flag An interrupt can be generated when the flag is set Doc ID 14153 Rev 2 15 25 www BDTIC com ST Memory management for IAP AN2659 4 4 4 4 1 16 25 Library support for Flash programming The STM8 firmware libraries available from www st com provide developed and verified functions for programming the Flash memory of every STM8 microcontroller family The functions support byte word and block programming and make it easier for developers to write their own programming code The library also includes functions for managing the programming code execution from RAM These functions are copy to RAM execution from RAM and storing functions in the Flash memory They are contained in the following files e library scr stm8x_flash c library inc stm8x_flash h These files contain the complete source code for Flash programming Refer to the library user manual FWLib stm8s_fwlib_um chm for help using the STM68 library Flash programming function list This list gives a short description of the STM8S Flash programming functions which are the same for STM8A and STMBL devices void FLASH_Delnit void Deinitializes the
11. demonstrator software August 2011 Doc ID 14153 Rev 3 1 25 www st com www BDTIC com ST Contents AN2659 Contents 1 Operation theory un ntsc EE sri oo a wt Dc in ca em a er De 5 2 STM8 devices with built in ROM bootloader 2000055 6 2 1 Implementation details EE EE EE ee ee 6 2 2 Adapting IAP master side to ROM bootloader protocol 7 3 User bootloader for STM8 devices 200 eee RR RR RR RR Re 8 3 1 User bootloader firmware example description EE EE 9 3 2 Configuring the user bootloader firmware example 12 4 Memory management for IAP 0 00 cece eee eee 13 4 1 Memory protection cece oor e toe nee DE FOSS WESE Rees eRe owed 13 4 1 1 Flash memory protection EE EE Ee tee 13 4 1 2 User boot code protection UBC 0 060 c eee ee 13 4 1 3 Vector table redirection 0 000 cece eee 14 4 2 Block versus word programming 0 eee eee eee 15 4 3 RAM versus Flash programming code location 15 4 3 1 Programming the data EEPROM area 0 000 ee eee 15 4 4 Library support for Flash programming 0 e ee eee eee 16 4 4 1 Flash programming function list EE EE eee 16 5 Configuring the Cosmic compiler for RAM code execution 18 5 1 Creating a segment in the STVD project anaana aaan 18 5 2 Creating a memory segment in the Cosmic linker file
12. one jump The only requirement for the user application is that the user interrupt table must be located at a fixed address This is because the primary interrupt table is not rewritable and jumps to the user interrupt table at a fixed address value see Section 6 Setting up your application firmware for user bootloader use Doc ID 14153 Rev 2 www BDTIC com ST AN2659 Memory management for IAP 4 2 4 3 4 3 1 Block versus word programming STMB8 microcontrollers contain a Flash type program memory where firmware can be writen There are two methods for writing or erasing Flash program memory e Byte word programming 1 or 4 bytes Advantages offers small area programming code can be executed directly on the Flash program Disadvantages program stops during programming programming speed is slow Block programming 128 bytes or 1 Flash block for a given STM8 device Advantages offers large area programming with high speed large blocks Disadvantages programming routine must run from the RAM need to copy programming routine into the RAM RAM versus Flash programming code location Depending on the selected programming method see Section 4 2 Block versus word programming the programming code must run from the RAM or from the Flash memory If the programming code runs from the Flash memory use only byte word programming to program the Flash memory During Flash memory programming
13. project main h This is done using the following code define MAIN_USER_RESET_ADDR 0x9000u1 Doc ID 14153 Rev 2 ky www BDTIC com ST AN2659 Conclusion 7 7 1 Conclusion The STM8 microcontroller fully supports IAP programming This feature allows the internal STM8 firmware to erase and write to any of its internal memories including the Flash program memory data EEPROM memory and RAM memory The short programming times inherent in such advanced technology can be further decreased by using fast programming mode if the destination memory is erased The STM8 RWW feature allows the microcontroller to stay at a high performance level even during Flash and or EEPROM memory programming The user bootloader application presented here provides designers with an IAP implementation that they can use to add IAP support into their own final products The bootloader code is designed to run in the STM8 family of microcontrollers Features in the final user bootloader application Bootloader activated by an external pin jumper on PCB Interrupt table redirection Executable RAM code management Library support for easier programming RWW feature High level C language usage Support for multiple communication interfaces UART SPI I2C Doc ID 14153 Rev 2 23 25 www BDTIC com ST Revision history AN2659 8 24 25 Revision history Table 1 Document r
14. the UBC part of the memory with an address range at the beginning of the Flash memory see Figure 6 User boot code area and user application area To correctly program your application firmware using the user bootloader you need to shift the start and vector table addresses of your application This avoids any Flash memory write in the area reserved for the user bootloader This is done in STVD by modifying the linker configuration You can access the linker by clicking on Project gt Settings then clicking on access to Linker tab and then selecting the input category In this way you can move your vector table and the Code Constants section according to the size of the user bootloader being used see Figure 8 Figure 8 Setting the project start and vector table addresses in STVD Project Settings Settings for Debug C Compiler Assembler Pre Link Linker Post Build N discover Category Input v Defaults Script Lkf file name OutputPath T argetSNam Ey MV Auto Vector file name Vector addr 4 sre stm8_interrupt_vector c E 09000 Segment Section name i Options Code Constants l Eeprom Zero Page Ram Command line cink ToolsetLibO pts o OutputPath T argetSName sm8 Al m ODutputPath T argetSName map se Cancel To finish the setup your new vector table address must be in line with the define variable MAIN_USER_RESET_ADDR in your user bootloader
15. u8 FLASH_ReadByte u32 Address Reads any byte from the Flash memory u16 FLASH ReadOptionByte u32 Address Reads one option byte void FLASH SetLowPowerMode FLASH LPMode TypeDef LPMode Select the Flash behavior in low power mode void FLASH SetProgrammingTime FLASH ProgramTime TypeDef ProgTime Sets the fixed programming time void FLASH Unlock FLASH MemType TypeDef MemType Unlocks the program or data EEPROM memory FLASH Status TypeDef FLASH WaitForLastOperation FLASH MemType TypeDef MemType Waits for a Flash operation to complete The STM8 library package also contains examples that show how to use these functions in the final source code Write your own code based on these examples Doc ID 14153 Rev 2 17 25 www BDTIC com ST Configuring the Cosmic compiler for RAM code execution AN2659 5 5 1 18 25 Configuring the Cosmic compiler for RAM code execution Block programming must be executed from the RAM memory Therefore the code to be copied into the RAM must be compiled and linked to be run in the RAM address space but it is stored in the Flash memory It is possible to write a simple programming code assembly taking care with the RAM addressing and then storing this code in the Flash example the code uses only relative addressing or RAM addresses However it is more efficient to use compiler support for this purpose Cosmic compiler support described below has these features built in Tw
16. 19 5 3 Finishing and checking the configuration 0 0 ee 20 6 Setting up your application firmware for user bootloader use 22 7 CONCIISIONS cis ctutiscae es ie RS ne oo er EE ele EG Br Bl ea Ba 23 7 1 Features in the final user bootloader application 23 8 REVISION history ses Ge ceded ve RA NN Me ee eee ea ee 24 2 25 Doc ID 14153 Rev 2 ky www BDTIC com ST AN2659 List of tables List of tables Table 1 Document revision history ie Ee Ee ee EE tees 24 ky Doc ID 14153 Rev 2 3 25 www BDTIC com ST List of figures AN2659 List of figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 4 25 Typical bootloader application 00006 5 Example of STM8S208xx bootloader a an EE EE ee Ge ee Ge ee ee ke ee 6 Example of user bootloader implementation in the Flash memory ii EE Es se 8 Example of the user bootloader package provided EE EE EE eee 9 Bootloader flowchart is EE EE Re ee ee GE SE ee ee ee Ee eee ee 11 User boot code area and user application area 0 00 ee ee 14 Define linker memory section in STVD 00000 ects 19 Setting the project start and vector table addresses in STVD 00 cease 22 Doc ID 14153 Rev 2 ky www BDTIC com ST AN2659 Operation theory Operation theory In practice IAP requires a bootloader implemented in the STM8 firmware that c
17. ame Fom To Options Code Constants 0x8080 Ox27fff Eeprom 024000 Ox47ff Zero Page 0x0 Duff Ram 0x100 0x13ff data bss Command line cink ToolsetLibOpts o QutputPath TargetSName sm8 A m OutputPath T argetSName map se 5 2 Creating a memory segment in the Cosmic linker file The second way to configure the Cosmic compiler for RAM code execution is to create a special memory segment which is defined in the linker file kf and marked by the flag ic An example of a RAM space segments definition in the linker file is as follows Segment Ram seg data b 0x100 m 0x500 n data seg bss a data n bss seg FLASH_CODE a bss n FLASH_CODE ic This example defines a RAM space from address 0x100 Firstly the data and bss sections are defined Then the code defines a moveable FLASH_CODE section where the routines for Flash memory erase and write operations are located This section must be marked by option ic moveable code Into the marked ic section put functions which should be compiled linked for RAM execution but which are stored in the Flash memory This is done in the source code by definiting a section as shown below ky Doc ID 14153 Rev 2 19 25 www BDTIC com ST Configuring the Cosmic compiler for RAM code execution AN2659 set code section to FLASH_CODE placement pragma section FLASH_CODE void FlashWrite void void FlashErase void
18. an communicate with an external master such as a PC via a suitable communication interface The new code can be downloaded into the microcontroller through this interface The microcontroller then programs this code into its Flash memory IAP can also be used to update the content of the internal data EEPROM memory and the internal RAM memory This operation is usefull when a microcontroler is already soldered in its final application and needs a firmware update Figure 1 shows a typical bootloader application Figure 1 Typical bootloader application RS232 TTL Bootloader enable converter Z jumper The bootloader is that part of the code which runs immediately after a microcontroller reset and which waits for an activation signal for example from grounding a specific pin or receiving a token from a communication interface If activation is successful the code enters bootloader mode If activation fails for example due to a timeout or the jumper on the pin not being present the bootloader jumps directly to the user application code In bootloader mode the microcontroller communicates with the external master device through one of the serial communication interfaces available in it UART SPI I2C CAN using a set of commands These commands are usually e Write to Flash e Erase Flash e Verify Flash Additional operations such as read memory and execute code from a given address jump to given address
19. es are the property of their respective owners 2011 STMicroelectronics All rights reserved STMicroelectronics group of companies Australia Belgium Brazil Canada China Czech Republic Finland France Germany Hong Kong India Israel Italy Japan Malaysia Malta Morocco Philippines Singapore Spain Sweden Switzerland United Kingdom United States of America www st com ky Doc ID 14153 Rev 2 25 25 www BDTIC com ST
20. evision history Date Revision Changes 20 Feb 2010 1 Initial release Document updated to include the whole STM8 family 10 Jun 2010 2 STM8A STMBL and STM8S Content of document restructured and rewritten 25 Aug 2011 3 Updated document references to bootloader manual in Section 2 2 Doc ID 14153 Rev 2 www B DTIC com ST AN2659 Please Read Carefully Information in this document is provided solely in connection with ST products STMicroelectronics NV and its subsidiaries ST reserve the right to make changes corrections modifications or improvements to this document and the products and services described herein at any time without notice All ST products are sold pursuant to ST s terms and conditions of sale Purchasers are solely responsible for the choice selection and use of the ST products and services described herein and ST assumes no liability whatsoever relating to the choice selection or use of the ST products and services described herein No license express or implied by estoppel or otherwise to any intellectual property rights is granted under this document If any part of this document refers to any third party products or services it shall not be deemed a license grant by ST for the use of such third party products or services or any intellectual property contained therein or considered as a warranty covering the use in any manner whatsoever of such third party products or services or
21. ich use a communication protocol IC not yet supported in the built in bootloader user bootloader firmware can be added and customized at the beginning of the Flash memory Figure 3 Example of user bootloader implementation in the Flash memory 0x8000 Interrupt vector table 0x8080 User bootloader 0x9000 EE UBC protected area ai17467 For this purpose an example of a user bootloader firmware is provided with this application note This package is divided into three main subdirectories each one dedicated to one STM8 family member STM8A STMB8L and STM8S Each directory is composed of the following components Sources containing the firmware source code Includes containing the firmware header file main h This file can be edited to configure your user bootloader see Section 3 2 Configuring the user bootloader firmware example e Flash loader demonstrator files contain all map files to add in the Flashloader demonstrator install directory to be compatible with the user bootloader e STVD containing a prebuilt project for STVD using a Cosmic or raisonance compiler Figure 4 shows an example of the the user bootloader firmware Doc ID 14153 Rev 2 ky www BDTIC com ST AN2659 User bootloader for STM8 devices 3 1 Figure 4 Example of the user bootloader package provided 5 Flash_loader_demonstrator_files HO STM84_User Bootloader_example includes sources 3 STD C
22. o processing methods can be used e Creating a segment in the STVD project Creating a memory segment in the Cosmic linker file Creating a segment in the STVD project The first step to create a segment in the STVD project is to define one section in your code example FLASH CODE and put your Block programming function inside This is done using the following code set code section to FLASH_CODE placement pragma section FLASH_CODE void FlashWrite void void FlashErase void set back code section to default placement pragma section The second step is to set the linker in your project settings window by clicking on Project gt Settings then clicking on access to Linker tab and then selecting input category In this way you can dedicate a memory area to your defined section FLASH CODE in the RAM Option ic must also be associated with this section see Figure 7 Define linker memory section in STVD Doc ID 14153 Rev 2 ky www BDTIC com ST AN2659 Configuring the Cosmic compiler for RAM code execution Figure 7 Define linker memory section in STVD Project Settings Settings for Debug X C Compiler Assembler Pre Link Linker Post Build HE Es stm8bootloader Category Input X Defaults Script Lkf file name OutputPath T argetSNam MV Auto Vector file name Vector addr stm8_interrupt_vector c Ed OxBOOO SegnentSecionn
23. osmic B STM8L_User Bootloader_example includes 2 sources STD Cosmic B STM85_User Bootloader_example includes 2 sources 3 STYD Cosmic User bootloader firmware example description The basic program flow of a user bootloader application is described in Figure 5 Bootloader flowchart After a device reset a selected GPIO can be used as a bootloader activation signal Depending on its logical state 0 V or 5 V the bootloader can be activated or not The bootloader configures this GPIO as input mode with pull up in order to detect any voltage variation If the pin voltage level is zero jumper present the bootloader is activated Otherwise the bootloader jumps to the reset address of the user application if this address is valid In the case of bootloader activation the chosen communication interface is initialized A timeout count is then activated i e 1 second If during this timeout nothing is received from the given communication interface UART SPI IC the bootloader jumps to the user application reset address If the user bootloader receive a valid activating token byte from the communication interface before the timeout elapses it then enters memory management mode to perform the following operations 1 Initialize the Flash programming routines by copying the programming functions to RAM 2 Wait in a loop for a valid command to be received from the master 3 Compute the received
24. st copy these sections from the Flash to the RAM before calling the RAM functions The Cosmic compiler supports this copying by a built in function int _fctcpy char name which copies a whole section from a source location in the Flash to a destination location in the RAM using the following code g 20 25 Doc ID 14153 Rev 2 www BDTIC com ST AN2659 Configuring the Cosmic compiler for RAM code execution void main void copy programming routines to Flash _fctepy F Define flash programming Time FLASH SetPprogrammingTime FLASH PROGRAMTIME STANDARD Unlock Program amp Data memories FLASH Unlock FLASH MEMTYPE DATA FLASH Unilock FLASH MEMTYPE PROG Just after the program starts the RAM section is copied from the Flash into the RAM by the function fctcpy F The function parameter b is the first character of the section name defined in the linker file F as FLASH CODE see linker file on page 19 The firmware can then call any of the FLASH_xxx functions in the RAM and execution is done only from RAM ky Doc ID 14153 Rev 2 21 25 www BDTIC com ST Setting up your application firmware for user bootloader use AN2659 6 22 25 Setting up your application firmware for user bootloader use The application firmware and the user Bootloader firmware must be developped as two different projects The user bootloader firmware occupies
25. the code cannot access the Flash memory the Flash is in programming mode Therefore program execution from the Flash is stopped during programming for several milliseconds and then continues This mode is useful in situations where only a small part a few bytes of the Flash memory needs to be updated or when it does not matter that programming is very slow To program a large Flash memory area with optimum speed block programming mode has to be used Block programming mode can be performed only by a code located in the RAM First copy the programming code into the RAM and then run jump to this code The RAM code can then use block mode to program the Flash In this mode programming one block takes the same time as programming one byte word in byte word mode Consequently programming speed is faster and code execution is not stopped because it is running from RAM The only disadvantage of this method is the RAM code management Copying the executable code to the RAM Storing the RAM code Allocating RAM space for the code Compiling the code to be able to run from the RAM Programming the data EEPROM area For data EEPROM programming the programming code does not have to be executed from the RAM It can be located in the Flash program memory even if block programming is used This read while write RWW feature speeds up microcontroller performance during IAP Only the data loading phase the part of code which loads
26. x8080 An important point to highlight in order to modify the vector table via IAP is that the main vector table should be redirected to another vector table located in the rewritable application code area see Figure 6 The only drawback of such redirection is the increase of the interrupt latency because of the execution of a double jump Doc ID 14153 Rev 2 13 25 www BDTIC com ST Memory management for IAP AN2659 14 25 Figure 6 User boot code area and user application area 0x8000 Interrupt vector table Tote 0x8080 User bootloader 0x9000 Firmware Interrupt vector table 0x9080 Firmware code 1 UBC protected area Redirection ai17468 More detailed information about memory map of specific STM8 device type can be found in the STM8 reference manuals and datasheets Vector table redirection As the initial interupt vector table address 0x8000 to 0x8080 is write protected by the UBC option it is mandatory to create another interrupt vector table to be able to modify it by IAP Vector table redirection is performed in the following way The start of the user application area contains its own interrupt table with the same format as the primary interrupt table The primary interrupt table contains a set of jumps to the user interrupt table If an interrupt occurs the user application is automatically redirected from the primary interrupt table to the user interrupt table by
Download Pdf Manuals
Related Search