PMOD-series-resistor-board

A PMOD carrier that drops a 200 ohm series resistor into every signal line. Four 2x6 PMOD sockets link through four resistor networks, so you can protect or damp an FPGA's IO without cutting traces.

What's on the board

• Four 2x6 PMOD connectors.
• Four 200R resistor networks (RN1-RN4).
• VCC and GND passing through between sockets.

The signal path

A PMOD plugs into one side and the next board into the other. Each signal line between the sockets runs through a 200R network element, while VCC and GND go straight across. I picked 200 ohms; it damps ringing without slowing SPI.