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Utilizar memoria flash para tabela de CRC #37

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Utilizar memoria flash para tabela de CRC #37

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17 changes: 17 additions & 0 deletions libraries/ModbusSerial/ModbusSerial.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -187,6 +187,7 @@ void ModbusSerial::task() {
_len = 0;
}

#ifndef USE_FLASH_PROGMEM
word ModbusSerial::calcCrc(byte address, byte* pduFrame, byte pduLen) {
byte CRCHi = 0xFF, CRCLo = 0x0FF, Index;

Expand All @@ -202,8 +203,24 @@ word ModbusSerial::calcCrc(byte address, byte* pduFrame, byte pduLen) {

return (CRCHi << 8) | CRCLo;
}
#endif



#ifdef USE_FLASH_PROGMEM
word ModbusSerial::calcCrc(byte address, byte* pduFrame, byte pduLen) {
byte CRCHi = 0xFF, CRCLo = 0x0FF, Index;

Index = CRCHi ^ address;
CRCHi = CRCLo ^ pgm_read_byte(&_auchCRCHi[Index]);
CRCLo = pgm_read_byte(&_auchCRCLo[Index]);

while (pduLen--) {
Index = CRCHi ^ *pduFrame++;
CRCHi = CRCLo ^ pgm_read_byte(&_auchCRCHi[Index]);
CRCLo = pgm_read_byte(&_auchCRCLo[Index]);
}

return (CRCHi << 8) | CRCLo;
}
#endif