Pendryx Pico

Shipped! (At least until I have approval for funding) The Pendryx Pico is a rpi Pico-sized devboard with 28 GPIO pins, including I2C (In order), and a mic. It has 520 KB of ram, 18 MB of flash memory, and connects via USB-C!

I have completed my PCB checks and finished labeling the board. All that is left before shipping is to complete the GitHub page and actually ship!

I DID IT! I managed to route the entire PCB, and fit all the components. The only thing I had to cut was the I2C header. However, It’s still accessible on the GPIO (In the correct order and including the needed resistors) So you could directly connect a display to it. All that’s left to do before I ship is to check all my work and do some more friendly labeling! (And of course the GitHub repo)

I managed to hook up the power and usb data to the actual rp2354a chip, including both the 3.3 and 1.1v connections. It’s a bit messy, but it worked. I’m currently trying to figure out how to attach my extra flash memory, since that chip isn’t exactly tiny, and it still needs to reach the correct pins on the core. I’ll also have to leave room for GPIO wiring. But I’m still hoping it will continue to go fairly well.

This one isn’t going to look like much progress per amount of time compared to the others, but here we go. I assigned pcb footprints to all my components. Then, I started on the pcb, only to realize that some of those footprints are a bit large for a 20 x 50 mm board. So after a lot of attempting to make it work, I finally changed to smaller resistor and capacitor footprints. I will also likely change my button and crystal footprints later, since they are a bit too large as well, but I’ll do that when I get to that part of the board. Anyway, I’m finished with the usb power and data parts of the pcb (for now) and have to do the main core and I/O next, which will likely be a pain, (Hence why my starting sections are so cramped) but I figured I should stop here to make a log. Hoping all goes well in the next steps!

Ok, so I’ve added an analog mic, as well as an extra 16 mb flash memory. So in theory you can store a decent amount of audio or whatever else on this thing. The mic won’t exactly be great quality, but it will work for general uses like sound activation. I’m tempted to add wifi, so I’m either going to do that next or start the PCB.

I finished the main schematic for the board by adding a status LED and setting up the IO pins. I think I might still add a few things before working on the PCB though. I’m considering extra flash memory and perhaps an inbuilt mic for some extra features. I may end up making some modules for this board later on. But here’s thee pictures!

I finished the USB data sheet. So now the board can actually send and receive data, which is rather important for a devboard. Lots of screenshots this time due to small changes to various parts of the schematic. Once I finish all the critical systems, I’ll add some of the things that will make it a bit different from a standard pico.

I updated the power sheet a bit. Then I worked on one of the more complicated parts of this schematic design; the core sheet. It took a little while, but I think it works, so long as I do the other sheets right of course. I also began my main schematic diagram since I have more than one sheet, and you can see the single 3.3v line from the usb-c power sheet running to the core! I know, exciting stuff, right? Anyways, I have a ways to go before I can work on the actual pcb, and will likely be adding some features to make it different from a basic pico, otherwise there wouldn’t be much point!

So I’ve decided to try making an Rpi Pico-esque devboard. Since I don’t have that much experience with such things, it’s a lot of trial and error, as well as referencing far too many things at once. I decided to start by trying to make the power delivery circuit. I’m not certain it is correct, but an attempt was made.