Getting the RP2040 and all the support components, which include an 8MB QSPI Flash chip, a 3V3 LDO, a handful of 0201 passives, and even a pair of pushbuttons, required quite a lot of design tweaking.

While the pinout is very similar to the Arduino Nano’s, there are four (12-bit) analogue inputs rather than eight (10-bit). Some digital GPIO pins are numbered differently too.