Difference between revisions of "ST STM32F4"
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The STM32F4 series devices provide some option bytes which allow some "permanent" configuration as well as readout protection for the device. Unfortunately, the option bytes become effective immediately when programmed. This means when enabling the read protection of the device via option bytes, the programmer will immediately lose the access to the flash, without any possibility to verify the complete flash operation. Therefore, the option bytes cannot be programmed as part of the flash image. The sequence, to program the option bytes consists of multiple read / write accesses to special function registers of the STM32F4 MCU. |
The STM32F4 series devices provide some option bytes which allow some "permanent" configuration as well as readout protection for the device. Unfortunately, the option bytes become effective immediately when programmed. This means when enabling the read protection of the device via option bytes, the programmer will immediately lose the access to the flash, without any possibility to verify the complete flash operation. Therefore, the option bytes cannot be programmed as part of the flash image. The sequence, to program the option bytes consists of multiple read / write accesses to special function registers of the STM32F4 MCU. |
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=== Via J-Flash=== |
=== Via J-Flash=== |
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| − | In order to program the option bytes, some exit-steps need to |
+ | In order to program the option bytes, some exit-steps need to be added to the J-Flash project. The exit steps will be executed at the end of an successful auto-programming process (''Target -> Auto''). J-Flash comes with an example project for the STM32F405OE which demonstrates how to program the option bytes ([[File:STM32F405OE_OptBytes.jflash]]). These steps can be adapted for all STM32F2 / F4 devices since they are compatible regarding option byte programming. The option byte values are transmitted in the step which writes the ''OPTCR''. Example project:<br> |
[[File:Wiki-STM32F4_OptionByteProg.png]] |
[[File:Wiki-STM32F4_OptionByteProg.png]] |
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Revision as of 10:22, 14 June 2016
Option byte programming
The STM32F4 series devices provide some option bytes which allow some "permanent" configuration as well as readout protection for the device. Unfortunately, the option bytes become effective immediately when programmed. This means when enabling the read protection of the device via option bytes, the programmer will immediately lose the access to the flash, without any possibility to verify the complete flash operation. Therefore, the option bytes cannot be programmed as part of the flash image. The sequence, to program the option bytes consists of multiple read / write accesses to special function registers of the STM32F4 MCU.
Via J-Flash
In order to program the option bytes, some exit-steps need to be added to the J-Flash project. The exit steps will be executed at the end of an successful auto-programming process (Target -> Auto). J-Flash comes with an example project for the STM32F405OE which demonstrates how to program the option bytes (File:STM32F405OE OptBytes.jflash). These steps can be adapted for all STM32F2 / F4 devices since they are compatible regarding option byte programming. The option byte values are transmitted in the step which writes the OPTCR. Example project:
