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DE10-Nano Problem

Posted: Sat Feb 13, 2021 3:34 am
by Blitzwing
Hi everyone,

I'll post here as I don't think I really put the original in the right place.

Recently built my MiSTer that I put together in July into a Node 202. Used three metal momentary LED buttons and wired those up correctly to the I/O 6.1 board headers, everything was ok except sometimes when I'd go to press a button the machine would reset, eventually figured it was static build up from my chair that was doing it through the unearthed case.

Turned it on a few days later and the power LED was dimmer than normal but still changing brightness, the user LED was lit all the time in the main menu, plugged the jumper in to turn the I/O board LEDs back on and it was the same on that.

Tried the I/O board in another de10 and it works perfectly.... Checked the voltages at the GPIO header, while at the main menu the power led goes up to 5v and down to 3.3v when it is pulled low, the user led is held constantly at 3v.

Now my question, do the GPIO pins go straight to the FPGA, or is there other SMD component that sits between it and the FPGA? If not I'm guessing I've damaged something in the FPGA itself.

Measurements:

Pin (1) user led negative to GND = 1.9v
Pin (11) (5v) = 4.9v
Pin (11) to Pin (1) = 3v

Pins 3 and 5 (disk and power LEDS) on the GPIO measure 1.8k ohm between those and ground, pin 1 (user LED) is a dead short.

Update: reading page 19 of the schematic it seems that apart from pins 11, 29, 12 and 30 which are vcc and ground then they all just go to the FPGA 😟 beware static people.

Thanks everyone.