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1. ɗ𐐩ʃƕρʋ (deshipu@fosstodon.org)'s status on Saturday, 26-Aug-2023 00:07:08 JST ɗ𐐩ʃƕρʋ

   I have insomnia again, and that means I'm designing PCBs again. I decided to move my design for the µGame 22 handheld console from my original design in Fritzing to EasyEDA. Got most of the largest components placed, now I need to find all the caps, resistors, crystal and flash memory, and also redo the power switching and stabilization – those are actually the new things for me.

   • minute (mntmn@mastodon.social)'s status on Saturday, 26-Aug-2023 00:07:06 JST minute

     in reply to

     @deshipu this is cool! i didn't realize there are games running on rp2040? how's the display controlled, is it a framebuffer on rp2040 + SPI?

   • ɗ𐐩ʃƕρʋ (deshipu@fosstodon.org)'s status on Saturday, 26-Aug-2023 00:07:07 JST ɗ𐐩ʃƕρʋ

     in reply to

     Looks like it just works? I'm shocked. I just soldered on the display (LCSC didn't have it in their parts, of course). I still need to test the sound, but everything else looks fine.

   • ɗ𐐩ʃƕρʋ (deshipu@fosstodon.org)'s status on Saturday, 26-Aug-2023 00:07:07 JST ɗ𐐩ʃƕρʋ

     in reply to

     Soo, after testing the sound, I have to conclude that... it works too well? I mean, it's much louder and clearer than with the transistor, and I can change the gain from 3dB to 15dB (at 15dB it starts crackling), and everything is great... as long as USB power is connected. When I switch to battery, any louder sound makes the backlight dim for a moment, and the loudest explosion sound makes the display reset and show the white screen of death.

     So I added a boost circuit. It's getting tight.

   • ɗ𐐩ʃƕρʋ (deshipu@fosstodon.org)'s status on Saturday, 26-Aug-2023 00:07:07 JST ɗ𐐩ʃƕρʋ

     in reply to

     It works! I used the batteries that were dead for the previous version, and it seems to be working off them perfectly fine now! Still the backlight is flickering a little bit when playing the loudest sound, but it will be perfectly fine with fresher batteries. Now just waiting for the pull request to #circuitpython to merge, and for more displays to arrive, to attach them to the remaining prototypes, and I see a game programming workshop in my future.

   • ɗ𐐩ʃƕρʋ (deshipu@fosstodon.org)'s status on Saturday, 26-Aug-2023 00:07:08 JST ɗ𐐩ʃƕρʋ

     in reply to

     Insomnia continues, so I made progress on the PCB. I think I'm happy with it, but I will look at it with fresh eyes in the morning.

     I used tiny resistors this time, which I do not have at home, so I guess I will have to order the board with assembly. LCSC has everything except the display, but I can add that myself easily.

   • ɗ𐐩ʃƕρʋ (deshipu@fosstodon.org)'s status on Saturday, 26-Aug-2023 00:07:08 JST ɗ𐐩ʃƕρʋ

     in reply to

     I gave it a day of rest, and pulled the trigger, it's now being fabricated by the good JLCPCB people.

     Apart from using a different PCB design program, there are a few differences from the previous prototype:
     - sound is now done with an I2S amplifier, not a simple transistor connected to a PWM output
     - there is a "perfect diode" circuit for switching power between the USB and battery
     - no reset and boot jumpers, hold the X button while connecting to get to boot mode
     - nice texture on the back.