Hello again, everyone. It's been a while since I posted anything, but I have been following along, and still reach for the Padauk MCUs occasionally for projects. Part of what has kept me from staying more excited has been the global component shortages and the fact LCSC currently has zero stock of Padauk MCUs.
Hopefully this is resolved soon.
Anyway, I thought I would post a new 'dev board' that I recently came up with to make breadboard prototyping a bit easier. One of the challenges has been having to physically move the MCU back and forth between the programmer and the breadboard. I did come up with the idea of using 1.27mm headers to turn the SOIC MCU into a pluggable module (see my post a few pages back). This helped, and I do use this with custom PCBs to make easier to test different code versions, but it still seemed a bit too annoying for breadboard prototyping.
This new 'dev board' solves the issue by using two DPDT switches that physically isolate the VDD (ICVDD), PA3 (ICPCK), PA5 (ICVPP), and PC6 (ICPDA) pins during programming from whatever is on the breadboard and vice-versa (see schematic). This means, all I have to do is flip the switches over towards the 2x4 programming header and run my programming command, and then flip the switches back to the other side to run the code. I had thought of using CD4053 analog switch ICs at first, but the design was getting too complicated, partly because of the different voltages in play, and I still needed a switch to change modes, so I backed away from that idea for now.
Anyway, here are the gerber files and schematic if anyone wants them. OSHPARK purchase link:
https://oshpark.com/shared_projects/BhdQLc4h. It is designed to work with either the PFS154 or PFS173 16-pin ICs. Technically it should also work with the PFC154 IC, although I don't have any of those to test with. I can post these files to a github repo if there is enough interest.
I use a 8-wire IDC cable with 2x4 female connectors on either end. One end plugs into an adapter that plugs into my easy-pdk-programmer, the other end plugs directly into this dev board. The DPDT switches are LCSC part number: C108742. Funny how they cost more than the Padauk MCUs.
Oh, yeah, there are also LEDs on PA3/PA4, and a Push Button on PA5/RST that make this ready to go for the examples found in the
http://github.com/free-pdk/free-pdk-examples repo.