int
iM880A_SendHCIMessage(uint8_t sapID, uint8_t msgID, uint8_t* payload, uint16_t length)
{
// 1. check parameter
//
// 1.1 check length
//
if(length > WIMODLR_HCI_MSG_PAYLOAD_SIZE)
{
return WiMODLR_RESULT_PAYLOAD_LENGTH_ERROR;
}
// 2. init TxMessage
//
// 2.1 init SAP ID
//
TxMessage.SapID = sapID;
// 2.2 init Msg ID
//
TxMessage.MsgID = msgID;
// 2.3 copy payload, if present
//
if(payload && length)
{
uint8_t* dstPtr = TxMessage.Payload;
int n = (int)length;
// copy bytes
while(n--)
*dstPtr++ = *payload++;
}
// 3. Calculate CRC16 over header and optional payload
//
uint16_t crc16 = CRC16_Calc(&TxMessage.SapID, length + WIMODLR_HCI_MSG_HEADER_SIZE, CRC16_INIT_VALUE);
// 3.1 get 1's complement
//
crc16 = ~crc16;
// 3.2 attach CRC16 and correct length, lobyte first
//
TxMessage.Payload[length++] = LOBYTE(crc16);
TxMessage.Payload[length++] = HIBYTE(crc16);
// 4. forward message to SLIP layer
// - start transmission with SAP ID
// - correct length by header size
if (ComSlip_SendMessage(&TxMessage.SapID, length + WIMODLR_HCI_MSG_HEADER_SIZE))
{
// ok !
return WiMODLR_RESULT_OK;
}
// error - SLIP layer couldn't sent message
return -1;
}
EXPORT long crc16_calc(void *data,uint32_t len,uint8_t low_endian)
{
uint8_t *buffer = (uint8_t*)data;
CRC16_Calc(buffer,len - 2);
if(low_endian) {
buffer[len-2] = CRC16_Low;
buffer[len-1] = CRC16_High;
} else {
buffer[len-1] = CRC16_Low;
buffer[len-2] = CRC16_High;
}
return 0;
}
EXPORT long crc16_check(void* data,uint32_t len,uint8_t low_endian)
{
uint8_t *buffer = (uint8_t*)data;
CRC16_Calc(buffer,len - 2);
/*
for(size_t i = 0; i < len; i++) {
fprintf(stderr,"%02X ",buffer[i]);
}
fprintf(stderr,"[%02X %02X]\n",CRC16_Low,CRC16_High);
*/
if(low_endian) {
return (buffer[len-2] == CRC16_Low) && (buffer[len-1] == CRC16_High);
} else {
return (buffer[len-1] == CRC16_Low) && (buffer[len-2] == CRC16_High);
}
}
