DKIT 9S12C32 common ground problems / hardware.

Started by Steven Bak March 26, 2004
I have interfaced an ultra-sonic transceiver to my mic.
PORTT channel 3 is pulled high to send send the sonic pulse, PORTT
channel 7 is polled to recieve the echo.

The transcevier measures distances perfectly on two conditions:
1. The common ground is connected to the ground probe of the logic
2. The power supply of my laptop is connected, and the laptop is
connected to the rs-232 of the docking module.

If either ground probe, the RS-232 connection, or the power the
supply of my laptop are removed, the transceiver stops working.

I was wondering if any one knew what could cause this problem??
Maybe some pins are needed to be tied to ground???

Thank you,


It sounds like the ultrasonic transciever and the HC12 board do not have
their grounds tied to each other. The logic analyzer and laptop tie the
grounds together via your power outlet, so it works when they are connected.

Jumper the transceiver's ground to the HC12 board's ground and see if that
fixes the problem.


Stephen Trier
Technical Development Lab
Cleveland FES Center / CWRU