PBJBread

The PBJ2 dual sequencer combined with an RP2040 onto a small Arduino-like breadboard-mountable PCB.

No input or output buffers – IO goes straight to the FPGA – so take care not to exceed the 3.3V power supply when driving.

pictures:

Pinout:

Schematics:

Note: do not back-drive the 5V from an external power supply on the Rev00 board.

Arduino example code:

The processor is a Raspberry Pi RP2040.  In the Arduino IDE, there are several compatible boards, but I've had the most success thinking of this as an Adafruit Feather RP2040

using the Arduino Philhower core.  Here are instructions for setting up the Arduino IDE with that core.

https://learn.adafruit.com/adafruit-feather-rp2040-pico/arduino-ide-setup

These examples can be run on a bare PBJBread, but it might be more convenient to mount it onto a small breadboard, like this:

Note that I've brought the 3.3V out to the rails, not the 5V, because the board's inputs are not 5V-tolerant.

The example code that follows needs GPIO1 wired to IN1, which is what the white wire is doing.

The first Arduino example goes over the basics of the PBJ, as well as the connectome and combinatorial logic modules.

The second example demonstrates using the serial port monitor to help debug PBJ code.

The third example shows the counter modes. 

The fourth example shows the second PBJ running a program asynchronously from the first.  Both PBJs use the counters as timeouts,

implementing a dual programmable one-shot.  So this is an expensive 74LS123 emulator.