Building my own stamp?

WKUadam

Hi I'm thinking about building my own basic stamp project, but I have a few questions before i start ordering parts. I know that parallax sells the interpreter chips/resonators and the memory chips. I've been looking at the schematics for the the stamps and it looks like the SIN and SOUT pins run directly to logic level converting transistors so i'm thinking that whats going to the tx and rx pins of the interpreter chip is TTL level serial signals (it makes sense if they are just specially programmed pic16's). If i'm right about the TTL signals, then think i could use USB and an FTDI chip and I could connect the TTL level directly to the TX an RX pins of the Interpreter chip(otherwise i would have to add a max232 and add the transistors etc). I was just wondering if anybody has tried this or am I correct about the TTL level?

Mike Green

Yes, the SIN, SOUT, and ATN lines are all logic levels. If you're going to use an FTDI chip, remember that the DTR line is used to force a reset. Use the USB BOE schematic as an example, but remember that the transmit and receive lines have an inverting transistor in them that's not needed if you make your own Stamp without the built-in inverters for those lines.

RobotWorkshop

If you want to build your own Stamp using the OEM chips like the BS2p40 then I have a board you can use as a carrier. There is some more information on this thread:

http://forums.parallax.com/showthread.php?t=114299

Robert

WKUadam

Thanks Mike that makes things a lot simpler I was originally thinking i might need an ftdi/max232 and all the transistors etc. This will save a lot of space.

Thanks Robotworkshop but i would rather build my own custom form factor its not really going to be a "stamp" more of an embedded microcontroller.

thanks for the help I'm off to design now