Created
October 19, 2015 10:35
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XMEGA NVM flash memory CRC compatible implementation in C
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/************************************************************************************************** | |
* XMEGA NVM compatible CRC32 | |
*/ | |
#define XMEGA_CRC32_POLY 0x0080001B // Polynomial for use with Xmega devices | |
uint32_t xmega_nvm_crc32(uint8_t *buffer, uint32_t buffer_length) | |
{ | |
uint32_t address; | |
uint32_t data_reg, help_a, help_b; | |
uint32_t crc_reg = 0; | |
for (address = 0; address < buffer_length; address += 2) | |
{ | |
help_a = crc_reg << 1; | |
help_a &= 0x00FFFFFE; | |
help_b = crc_reg & (1 << 23); | |
if (help_b > 0) | |
help_b = 0x00FFFFFF; | |
data_reg = (uint32_t)((buffer[address + 1] << 8) | buffer[address] & 0xFFFF); | |
crc_reg = (help_a ^ data_reg) ^ (help_b & XMEGA_CRC32_POLY); | |
crc_reg = crc_reg & 0x00FFFFFF; | |
} | |
return crc_reg; | |
} |
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