Service manual

8 Trouble Shooting

8-8 SAM4S ER-650 SERIES

8-8 RS-232C Serial Communication Problem

End

RS-232C Problem

Loop Back

Failure ?

1. Perform the “SELF TEST” in the S-MODE using the

Loop Back test Connector.

2. Check the connection of the RS-232C Connector and

Loop Back Connector.

3. Check the Txd,Rxd Pin on CPU.

4. Check the MAX232 Driving Chip and related Circuit on

I/F PBA.

Communication

Failure?

1. Check the connection of the RS-232C Connector and

Other side.

2. Check the I/F Cable whether it is open or short.

3. Check whether Signal is affected by the Cable Noise.

H/W Handshake

Ok?

1. Check the connection of the H/W handshaking

Line and Other side

2. Check the I/F Cable whether it is open or short.

3. Confirm the H/W handshaking Protocol.