Basic Stamp PCB

MR

I am designing a Printed Circuit Board for my Clock Project. Does the BS2 P40 have an on board Voltage Regulator on the stamp itself? or do I need to add one to the PCB? Should I connect the VCC to the VIN pin? Any other ideas or concerns that I should keep in mind? In addition I would like to add a D Sub connector to the PCB in case I need to update the code, how do I do this?

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Mike Green

The BS2p40 has a regulator on the module to supply the processor and a little bit more. If you have a 5V supply on your PCB, you connect that to the Vdd pin and leave Vin unconnected. If you still want to supply the Stamp with unregulated power, connect that to Vin and you can use some of the current from Vdd to power a few low current items. Vin needs to be a minimum of 5.5V.

There's a diagram in the Stamp Basic Manual showing how to connect a DB9 connector for programming. I think it's on page 28. There's also a diagram on the BS2p40's schematic downloadable from the webstore page for the BS2p40.

The regulator is an LT1121. This is rated for a maximum current of 150mA, but practically is limited by power dissipation. The closer Vin is to 5.5V, the less heat will be dissipated for a given amount of current. The Stamp itself takes about 40mA when running.

Post Edited (Mike Green) : 4/4/2009 4:56:54 AM GMT