         
         Serial.write(MAVLINK_BEGIN);	//start mark
         Serial.write(13);				//payload len
-        Serial.write(CMD_CAN_SEND);		//cmd
-        Serial.write(&canId, 4);		//addr
+        Serial.write((uint8_t)CMD_CAN_SEND);		//cmd
+        Serial.write((uint8_t*)&canId, 4);		//addr
         Serial.write(len);				//len
         Serial.write(buf, 8);			//data
         

//Can-bus shield
// the cs pin of the version after v1.1 is default to D9
// v0.9b and v1.0 is default D10
const int SPI_CS_PIN = 9;//10;
MCP_CAN CAN(SPI_CS_PIN);  // Set CS pin

struct CMD_STREAM

	uint8_t m_pBuf[CMD_BUF_LEN];
};
CMD_STREAM m_cmd;

void command(void)
{
