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https://github.com/lumapu/ahoy.git
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6ed2dfde9c
* fix negative temperature (OpenDTU issue 246) * added plausibility check based on payload length * prepared project for splitting into library and end-user-esp * added donation link to index.html * deactivated disclaimer temporarily
35 lines
1.1 KiB
C++
35 lines
1.1 KiB
C++
//-----------------------------------------------------------------------------
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// 2022 Ahoy, https://github.com/lumpapu/ahoy
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// Creative Commons - http://creativecommons.org/licenses/by-nc-sa/3.0/de/
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//-----------------------------------------------------------------------------
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#include "crc.h"
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namespace ah {
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uint8_t crc8(uint8_t buf[], uint8_t len) {
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uint8_t crc = CRC8_INIT;
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for(uint8_t i = 0; i < len; i++) {
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crc ^= buf[i];
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for(uint8_t b = 0; b < 8; b ++) {
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crc = (crc << 1) ^ ((crc & 0x80) ? CRC8_POLY : 0x00);
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}
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}
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return crc;
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}
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uint16_t crc16(uint8_t buf[], uint8_t len, uint16_t start) {
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uint16_t crc = start;
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uint8_t shift = 0;
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for(uint8_t i = 0; i < len; i ++) {
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crc = crc ^ buf[i];
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for(uint8_t bit = 0; bit < 8; bit ++) {
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shift = (crc & 0x0001);
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crc = crc >> 1;
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if(shift != 0)
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crc = crc ^ CRC16_MODBUS_POLYNOM;
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}
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}
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return crc;
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}
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}
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