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Add CRC check of the settings frame #17

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Add CRC check of the settings frame #17

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8b10674
Improve output format of the settings frame (#16)
syssi Jun 29, 2024
af8e1ee
Add CRC check of the settings frame
syssi Jun 29, 2024
182113e
De-reference
syssi Jun 29, 2024
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21 changes: 21 additions & 0 deletions components/lolan_bms_ble/lolan_bms_ble.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -402,6 +402,11 @@ void LolanBmsBle::decode_settings_data_(const std::vector<uint8_t> &data) {
ESP_LOGI(TAG, " Discharge cell voltage: %.3f V", ieee_float_(lolan_get_32bit(100)));

// 104 2 0x35 0xe2 CRC?
ESP_LOGI(TAG, " CRC: 0x%02X 0x%02X (0x%04X)", data[104], data[105], lolan_get_16bit(104));
uint16_t remote_crc = lolan_get_16bit(104);
uint16_t computed_crc = crc16(data.data(), 104);
ESP_LOGI(TAG, " Computed CRC: 0x%04X", computed_crc);

// 106 2 0x5a 0xa5
}

Expand Down Expand Up @@ -544,5 +549,21 @@ std::string LolanBmsBle::bitmask_to_string_(const char *const messages[], const
return values;
}

uint16_t crc16(const uint8_t *data, uint8_t len) {
uint16_t crc = 0xFFFF;
while (len--) {
crc ^= *data++;
for (uint8_t i = 0; i < 8; i++) {
if ((crc & 0x01) != 0) {
crc >>= 1;
crc ^= 0xA001;
} else {
crc >>= 1;
}
}
}
return crc;
}

} // namespace lolan_bms_ble
} // namespace esphome
2 changes: 2 additions & 0 deletions components/lolan_bms_ble/lolan_bms_ble.h
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Original file line number Diff line number Diff line change
Expand Up @@ -171,6 +171,8 @@ class LolanBmsBle : public esphome::ble_client::BLEClientNode, public PollingCom
}
};

uint16_t crc16(const uint8_t *data, uint8_t len);

} // namespace lolan_bms_ble
} // namespace esphome

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