by msarnoff on 5/12/24, 2:16 AM
I used Charlieplexing to drive four LEDs, four buttons, and a beeper from a 6-pin PIC10F200 with only four GPIOs. (and one is input-only!) It was a lot of fun working out the correct TRIS/GPIO combinations. (and fitting the whole thing into 256 instructions and 16 bytes of RAM was fun too)
https://github.com/74hc595/TinySimon
by voakbasda on 5/12/24, 2:35 AM
In the early 00’s, I used this technique to write a keyboard driver for a handheld computer, using a PIC microcontroller. The method was shown to me by a senior EE who previously worked on HP calculators, after HP had outsourced that division to another country. I learned a lot of tricks like that while at that job, as I was the only one on the team who was not a former senior HP engineer. They knew their stuff, and their stories about the outsourcing made me forever reluctant to buy anything made by HP.
by Ductapemaster on 5/12/24, 6:47 AM
Funny to see this here — as part of a project in my “writing for engineers” class my freshman year of college, I created this page!
by tomphoolery on 5/12/24, 3:38 AM
I always thought Charlieplexing was when you go on a tirade about Pepe Silvia and how Carol doesn't actually exist.
by runfaster2000 on 5/12/24, 5:25 AM
by noobermin on 5/12/24, 8:32 AM
I feel like for those of us who aren't serious electricians but do arduino like thing's we've done this, I just didn't know it had this name.
by wepple on 5/12/24, 2:10 AM
This is nifty. I noticed a lot of the adafruit LED displays were charlieplexed but never figured to look up what that meant.
by dvh on 5/12/24, 11:26 AM
Is it practical or should I just use i2c expander?