I'm trying to send a simple numerical value from RealTerm (terminal program) to the NXT via Bluetooth. According to Lego's Bluetooth SDK, the Write command follows two bytes that specify the length of the package:
Length bytes: LSB followed by MSB (e.g. 6 bytes: 0x06 0x00)
Byte 0: 0x00 or 0x80 (direct command with or without response)
Byte 1: 0x09 (write command)
Byte 2: Mailbox number, 0-9
Byte 3: Message size (including null termination byte)
Byte 4-N: Message data, where N = Message size + 3 (including null termination byte)
Following the manual's instructions, I've formulated a command sequence to send a "1" to the NXT, i.e. 0x06 0x00 0x00 0x09 0x00 0x02 0x01 0x00.
On the NXT, I have constructed a simple NXT-G program to display the received data. The program is similar to the picture shown in the following URL albeit with a couple of minor differences. The data type is a number instead of a char/text, and a number-to-text block has been added before the display block.http://www.legoengineering.com/activiti ... eceive.jpg
Unfortunately, the output on the display is always zero regardless of the value transmitted. Treating the received data as a text (instead of a number) produces a blank output. Transferring the display block inside the BT-receive loop doesn't help either. I've placed a sound block right outside the loop to detect breaks, and it does beep every time I send the command sequence. So, it's obvious that the NXT is receiving data. The status byte in the return data package shown on RealTerm is a further confirmation of the fact.
So, why is the value of the received data always zero? Or have I processed it incorrectly? Any help or insight would be really appreciated. Thanks very much.