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WIP modbus write

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This commit is contained in:
Duke NUCem 2021-10-10 11:35:14 +02:00
parent 917886820d
commit 051509155e
1 changed files with 22 additions and 14 deletions
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10
fw/Core/Src/modbus.c
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@ -65,7 +65,7 @@ int8_t modbus_copy_reply_to_buffer(uint8_t *buffer, uint8_t *msg_len, modbus_tra
if (transaction->function_code | MODBUS_ERROR_FLAG) {
/* sending error reply */
buffer[2] = transaction->exception.exception_code;
}
} else {
switch (transaction->function_code) {
case MODBUS_READ_HOLDING_REGISTERS:
case MODBUS_READ_INPUT_REGISTERS:
@ -79,6 +79,14 @@ int8_t modbus_copy_reply_to_buffer(uint8_t *buffer, uint8_t *msg_len, modbus_tra
buffer[4 + 2*i] = transaction->buffer16b[i] & 0xff;
}
break;
case MODBUS_WRITE_SINGLE_REGISTER:
buffer[2] = (uint8_t) (transaction->register_address >> 8);
buffer[3] = (uint8_t) transaction->register_address;
buffer[4] = (uint8_t) (transaction->holding_registers[0] >> 8);
buffer[5] = (uint8_t) transaction->holding_registers[0];
*msg_len = 8;
break;
}
}
crc16 = modbus_CRC16(buffer, *msg_len - 2); /* last two bytes is the checksum itself */
buffer[*msg_len - 2] = crc16 & 0xff;