question on programming the BS2 in-circuit

john lynch

Hi there,
I have built a small circuit around my BS2 and am wondering now before I power things up is it ok to program the stamp within the circuit, or must I pull it out every time I need to tweak the software and reprogram it on a second carrier board? I have the feeling I don't need to pull the stamp but would like a confirmation of this
thanks
John.

Martin_H

Yes, if this is the BS2 module then some of the pins on it accept connections from an RS-232 port as long as you have the capacitor from DTR to the atn pin. Like this:

;----/\/\/-----;-----||-----DB9S (pin4)
|      3.3k    |     0.22 (optional)
|------||------|
|     0.1      |
ground        atn

PS ascii art borrowed from http://www.emesystems.com/BS2rs232.htm but it was murder getting it to look right.

Post Edited (Martin_H) : 8/5/2010 2:10:28 AM GMT

Mike Green

The Stamp Reference Manual (and Stamp Editor help files) shows the circuit used on the Board of Education for programming via an RS232 serial port. You can use the same thing. The Stamp is intended to be programmed in-circuit.

john lynch

Thanks, I am using the Board of Education Development Board (USB) as a part of my circuit, (although I am feeding the Vdd with 5v from my own circuit's regulator rather than using the on-board regulator). I guess the stamp stops executing it's code when you download new code to it?

Mike Green

Yes. The ATN signal is actually a reset signal. The PBasic interpreter in the BS2 gets reset and looks for a signal on the serial input line that tells it to download a new program.