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memory protection: do not write reserved bits (#138)

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mruddy 2017-01-26 10:07:45 -05:00 committed by Pavol Rusnak
parent 14399f100e
commit 228a109e5f
1 changed files with 13 additions and 3 deletions
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16
memory.c
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@ -27,13 +27,23 @@
void memory_protect(void)
{
// Reference STM32F205 Flash programming manual revision 5 http://www.st.com/resource/en/programming_manual/cd00233952.pdf
// Section 2.6 Option bytes
// set RDP level 2 WRP for sectors 0 and 1
if ((((*OPTION_BYTES_1) & 0xFFFF) == 0xCCFF) && (((*OPTION_BYTES_2) & 0xFFFF) == 0xFFFC)) {
if ((((*OPTION_BYTES_1) & 0xFFEC) == 0xCCEC) && (((*OPTION_BYTES_2) & 0xFFF) == 0xFFC)) {
return; // already set up correctly - bail out
}
flash_unlock_option_bytes();
// WRP + RDP
flash_program_option_bytes(0xFFFC0000 + 0xCCFF);
// Section 2.8.6 Flash option control register (FLASH_OPTCR)
// Bits 31:28 Reserved, must be kept cleared.
// Bits 27:16 nWRP: Not write protect: write protect bootloader code in flash main memory sectors 0 and 1 (Section 2.3; table 2)
// Bits 15:8 RDP: Read protect: level 2 chip read protection active
// Bits 7:5 USER: User option bytes: no reset on standby, no reset on stop, software watchdog
// Bit 4 Reserved, must be kept cleared.
// Bits 3:2 BOR_LEV: BOR reset Level: BOR off
// Bit 1 OPTSTRT: Option start: ignored by flash_program_option_bytes
// Bit 0 OPTLOCK: Option lock: ignored by flash_program_option_bytes
flash_program_option_bytes(0x0FFCCCEC);
flash_lock_option_bytes();
}