Micro DSMC hookups


I just bought a micro DSMC and was eager to get started messing around with it and a Basic Stamp IIsx. I checked and double checked my connections, and just as a test loaded the small program at the end of the documentation. I was disappointed to find no response from the motor I had connected.

I am using a Board of Education with the small breadboard used for making the circuit. I have a lab power supply to provide 9 V to the motor, with the + of the supply going to Pin 1 on the DSMC, and the - of the supply going to Pin 2 on the DSMC. Pin 2 is also connected to Vss on the BOE. Pin 3 on the DSMC is connected to Vdd on the BOE. Pins 4 and 5 are connected to the reset and control lines from the Stamp, and Pins 6 and 7 are going to the motor leads. To me, this seems correct, based on the connections shown in the documentation.

I did a little investigating with a multimeter, and found that all the correct voltages are present at the appropriate pins (9 volts at Pin 1, 0 volts at Pin 2, 5 volts at pins 3, 4, and 5), but found that Pins 6 and 7 are both receiving about 0.22 volts, with 0 volts across the motor leads themselves (I would expect something slightly less than 9 volts).

What gives? Did I somehow blow the DSMC? The connections seem straightforward to me, but somehow I’m missing something.

Please advise.


Jeffrey Sabala


It sounds like you have made all of the connections to the micro motor controller correctly, and your problem is probably with the software.

The sample program in the instructions is for a BASIC Stamp II; you need to change the baud rate setting for the much faster BSIIsx to get it to transmit a valid baud rate. You should use a baudmode value of 240 instead of the 32 given in the BSII example.

For more details about using the serout command, check the BASIC Stamp documentation (starting on page 293 in revision 2.0c).

- Jan


Thanks for the tip on chaning the value for the Baud mode. That worked like a charm.

Thanks also for the reference to the STAMP SEROUT documentation - I’ll take a look at that.


Jeffrey Sabala