Create your own OysterPMOD, with a 8x8 led matrix, and a 128x128 OLED display ! It can be assembled without any soldering. It is compatible with all femtorv processors and supported boards, and uses a single PMOD connector.
You will need:
- an old plastic card (Oyster card, credit card ...)
- a MAX7219 driven 8x8 led matrix (costs around $2)
- a SSD1351 128x128 oled display (costs around $10 - $15). You may find cheaper clones, but they are sometimes reported not working.
- female-female dupont connecting wires for the led matrix
- connecting wires for the OLED display (most of the time they are shipped with it)
- small screws
- a 2x6 pins header (or two 1x6 headers)
- drill holes in the plastic card
- attach the led matrix and the OLED display to the plastic card
Insert the 2x6 pins header in the PMOD. The image shows what it looks
like on the IceBreaker (left) and IceStick (right). On the IceStick,
I like to stick a tiny rectangle of red adhesive tape to indicate where
the number 1 pin is.
Connect the wires of OLED screen to the headers as indicated on the
diagram. Use 5 female-female dupont wires to connect the led matrix.
Wonderful ! Both exactly fit in a single PMOD connector.
Use adhesive tape to fix the 12 wires together. Add a tiny rectangle of
red tape to indicate number 1 pin. Your Oyster PMOD is ready to be
used ! If you have multiple FPGA boards, with a bit of care, it is
quite easy to have a single Oyster PMOD and connect it / disconnect
it multiple times (without having to connect all wires one by one).
FemtoRV32 support libraries can redirect printf()
to the led matrix,
to the OLED screen or to the UART. It has also some basic drawing
functions for the OLED screen.