Serial Issue

[pkumar]

Serial Issue

Problem:

Not able to receive the proper voltages on the serial chip U27 on board.

Connection Diagram:

see attached file

Wrokouts:

1. As shown in the figure a extranal device is connected to Flo with help of 14 pin cable.

2. 14 pin cable in turn goes to serial chip U27 in device i.e Flo

3. The connection is Tx to Rx and vice versa for connecting external device and Flo.

4. Now external device sends the serial information on the serial connection that in turn Flo should receive at U27.

5. It receive the serial information means that there should be some voltage change at Tx and Rx pin of U27 on Flo (For ex. Say voltage rise from 0v to 0.5v).

6. We design an application which manipulate the signal received at U27 and display what it receive on screen.

7. But we major the voltage at U27 and actually we have not seen the proper voltage at U27 Tx and Rx pin.

8. So I doubt if it receives the signal or not.

9. The Signals sent by external device that Flo receive on Rx are :

Hire : |TA|TF000024000000000000030000000000000000

Stop : |TI|TF000024000000000000020000000000000000

10. We just want to listen the signal sent by external device.