Read serial data output from PIC Microcontroller using basic Stamp

LW

This is my first post. I have a small device that contains a pic microcontroller, when this device is powered up it outputs serial data, The data is repeated continually until the unit is disconnected. This unit has three leads 12v +, -, and data out. I want to read this data using a Stamp and then display the data on the screen.
I have no idea what form the serial data is in re Baud etc.I have tried connecting the Pic unit and the stamp together and tried virtually every baud setting but cant seem to get anything meaningfull from it. Just lots of odd symbols.

The Pic Microcontroller is 12F629
The stamp is BS2
Any help or ideas greatly apreciated.

Lynton
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stamptrol

Lynton,

Welcome tthe Forums.

While the concept of serial communication is quite simple, the details can make it seem complicated.

There are three things that have to be right before the two devices can communicate:

1. the baud rates have to be identical
2. the voltage levels of the data streams must be the same (or at least compatible).
3. the data formats have to be identical ( number of start, data and stop bits)

The odd symbols you are getting reflect some mis-match in one or more of the three criteria.

If you have no idea what the PIC is supposed to be putting out, it really will be quite a process to try all possible combinations. If you have access to an oscilliscope, it may make it easier to troubleshoot.

As a guess, assuming the PIC and Stamp are connected directly from pin to pin (no rs-232 level shifter involved), set the Stamp to use inverted mode and start with 9600 baud, 8 data, 1 stop bit. Then, proceed to change one criteria at a time. Work with baud rate first. The Stop bit setting likely won't change.

If the PIC device is commercially produced, try to get the information from the manufacturer. It will make life very much easier in getting the two devices to talk!

Good luck.