Introducing the Raspberry Pi Full GPIO level converters & monitoring

So I spent my last week end working on a full 3V3 to 5V level translator for my Raspberry Pi®. What I mean by “full” is that all the RPi GPIOs (17 lines) have their own translator. I didn’t find such a board on the market so here it is!

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I am using a simple voltage translator based on an N-channel MOSFET (the BSS138) and 2 resistors. The schematic was found in this very interesting NXP application note: Bi-directional level shifter for I²C-bus and other systems.

The board is designed as a stackable, in-between, expansion board on the RPi P1 connector. All 3.3V level GPIOs are connected to the bottom connector, translated to 5V and then, available on the top connector to make it easy to stack different expansion boards.

The 5V converted GPIOs are also available on a mini prototyping area. Useful if you just need to test one IC or need to connect the GPIOs with custom connectors.

Finally, I have also added a GPIO monitoring: each pin is connected to a LED so you can monitor the status of the GPIO in real time. The LEDs are buffered so they don’t have any influence on other connections you can make with the GPIOs.

Next steps are to mount the first prototype boards and start the debugging. That will be for my next post!