Serial Packets and ME/RealPort

I’m using an ME and the PC RealPort software. My board sends data to the PC in various sized packets. However, the PC only receives the entire packet if my device sends and extra byte, later. It would appear that either the ME or the Realport driver (not sure which) doesn’t send data unless it is either a full buffer worth, or it is old and more data comes in. PortMon shows it like this:

PC> 01 09 00 02 03 F1
Digi> 01 89 90 02 … 00 (missing last two bytes)
PC> 01 09 00 02 03 F1
Digi> 03 C6 01 89 90 02 … 00

Note the first two byts of the second response. Those are the missing two bytes from the first response.

Any idea what could be wrong?


I was having similar problems and I did two things, (I don’t know which solved it).

  1. Tied all the Hardware handshaking high.
  2. Put a small delay after sending [tx_thread_sleep(100)] so the ME can catch up.


Having the same problem I was not able to fix the problem with your description. Sending extra characters makes the problem worse.

I have already file a support case, but maybe someone in the forum has a solution?