Mini Review: RP2040 Pi Zero

It is common to see confusion between the Raspberry Pi Pico and other Raspberry Pi boards. The RP2040 Pi Zero, from Waveshare, makes it even more confusing, putting an RP2040 microcontroller in a Pi Zero form factor (including a mini HDMI connector).

At the heart of this board, we have the same RP2040 with a 12MHz crystal as the Raspberry Pi Pico. 16 Mbytes of flash memory and buttons for Reset and Boot are provided. There is a power LED but no LED connected to a GPIO. You can solder a three-pin header for debugging. A USB-C connector is connected to the USB pins in the RP2040 and can be used to power the board.

There is also provision for a lithium battery to power the board. The battery is charged when power is applied through the USB-C or the expansion connector. A micro SD slot is connected to GPIO 18, 19, 20 and 21.

So far, nothing that will rise our eyebrows, just a nice RP2040 board. The expansion connector is 40 pin header similar to the one in the Raspberry Pi Single Board Computers. Some Raspberry Pi hats (expansion boards) should work with the RP2040 Pi Zero, as long as you can figure out the software side.

A second USB-C connector, labeled PIO-USB, is connected to GPIO6 and GPIO7. It is meant to be used with a PIO/software USB implementation, but you could use it as a very confusing GPIO connector.

Last, but not least, there is the mini HDMI connector. This is actually a DVI interface that uses various GPIOs. Its use requires special software that uses DMA, PIO, and overclocking to generate the required signals.

Of course, this board will not run Linux (but there are ports of a couple of Unix-like operating systems for the RP2040, with no DVI support).

DVI software support is very sketchy right now. There are two examples at the Waveshare wiki, based on the ones found at https://github.com/Wren6991/PicoDVI.

Should you buy this board? The answer depends on your application. The HDMI/DVI interface will be useful only if you have the knowledge and time to develop a special application or if you find someone who has done that (serial terminal and old computer emulation are likely candidates).

If you will not use the HDMI connector, you get a nice 16M RP2040 board with battery support, an SD card slot, and a second USB-C connector. In some cases, the 40-pin connector will allow you to use an existing Rapberry Pi hat. All this could reduce the amount of connections and external hardware when compared to the Pi Pico.

More details can be seem at the Waveshare wiki,