Custom Stamp modules – Propeller, SX48, and OEM Stamp
As I was learning more about the Parallax OEM Stamp, SX48, and Propeller chip I designed some small boards that used each processor and put them in a small DIP-40 module that was with the same pin out as the 40-pin BS2p40 Stamp from Parallax. With those I could order an OEM BASIC Stamp chip from Parallax (based on the SX48) and then use them to create my own module. Using the EEPROM in DIP form factor I could use my SW2EEPROM adapter board to bank switch out different programs.
A step up in performance was just switch over to the native SX48 chip instead of using interpreted BASIC. Using the SX48 directly gives direct access to all the pins, interrupts, and the counter/timers built-in. It could be programmed in compiled SX/B so it wasn’t all that different from using the Stamp or Assembly code could be used where needed.
This was intended to be a kit that people could build if they wanted to work with the SX48 and enabled the SX48 to be easily used on a breadboard. Although the kits are no longer for sale I still have some of the blank PCB available if you want to build your own module.
To keep with the same form factor I was able to design one more module based on the Parallax Propeller processor. It too uses the same pin out as the BS2p40 module. In some cases it could drop right in place of a BS2p40 Stamp but other times a few changes were needed since the Propeller runs at 3.3V instead of 5V. To help each of the I/O pins had a small set of pads connecting to the actual pin at the edge of the module. This could be solder-bridged if you just wanted a direct connection. Alternately you could install a tiny surface mount resistor between the Propeller pin and the output pin at the edge of the board. It has an on-board 3.3v regulator, 5mhz xtal, 32K EEPROM in socket, and max3232 chip w/reset wired so the same Serial cable used for programming the BS2p40 module works! Any one of the three can now be interchanged in the same 40-pin socket (or circuit wired on a breadboard). These were designed so the could have been an upgrade path for someone that needed to retrofit an existing design that had a BS2p40 and wanted to move to the Propeller. Although it was a cool project there wasn’t enough of a need to have a batch of the boards produced.