PineWatch-Nixie tube watch-core board

The Nixie tube is connected through a 7-hole pin header. Compared with similar Nixie tube watch designs, the Nixie tube no longer needs to be fixed to the base plate by welding, and the Nixie tube can be replaced more flexibly. At the same time, the battery and wireless charging coil are both detachable, and a five-hole 2.0 download interface is reserved at the bottom, which can be downloaded directly using the download probe, which greatly facilitates the debugging process.

Issues to note:

1. Due to the chip pin design problem of the wireless charging receiving chip CP2022, the QFN package pins do not extend beyond the edge. There is a higher possibility of virtual soldering during welding, and the edge is more difficult to tin than other QFN chips.

2. It is necessary to add a magnetic isolation sheet (can be purchased online) between the receiving coil and the PCB, otherwise the PCB will be seriously heated during charging.

3. Due to chip shortage, the 3.3V power supply chip TPS62824DMQ has increased dozens of times. It is recommended that those who want to change the board use other Buck-Boost chips (such as TPS63802) or LDOs with an output of more than 500mA.