I am excited to hear some updates gmarsh! For some reason, my U1273a got real dim with missing pixels after being shipped across the pacific...
Which display did you end up buying? If you need help with PCB design and/or testing, I am happy to oblige!
Time for another update I guess:
- I sniffed the screen activity some more, to get a full idea of what the meter writes to the display.
- The lowest column address value sent to the screen is 0x02, which causes the column shift everyone is seeing. So all we need to do is subtract 2 when an address is written to the screen and that should center everything properly, and since the address is sent LSB-first from meter to screen (on the 1253A, at least) we can do that.
- The Verilog I posted earlier will wreck some command arguments that are sent to the screen on startup, so don't use it
I've got newer CPLD code now which looks for commands that take an argument and passes through the argument unmodified, and still fits in a 5M40ZE64 CPLD with ~60% utilization. I'll probably throw down a 5M80 for the first prototype run in case I run into any surprises.
- And I've got a new PCB designed, which I'll be ordering in the next week or so.
I'm also laying out a tester PCB that a display plugs into so I can measure all the rail voltages, program the CPLD and show a test screen on the OLED without having to use a real (and expensive) meter as a host. I'm also finishing a couple other projects to make one big JLCPCB order (+ one big Digikey order) at once.
I ended up ordering this screen afterwards:
https://www.aliexpress.com/item/4000321242073.htmlI don't need any help with the PCB design, but my big question is whether what I'm doing here for the U1253A can drop into your U1273A. Any chance you've got a 4 channel scope or MSO or anything that can capture what gets written from the meter to the display?