MiSTer FPGA Forum

Hi all, weird one this...
The POWER LED on my analogue IO Board 6.1 has stopped working completely, but USER and DISK are working fine. The LEDs on the nano are dancing nicely. Same result using the header, even if I remove the P5 (led power) jumper. I've checked switches on the nano are in the right place just in case that had an impact

I've had a scope of pin 5 on the IO board connector and that's holding at 3.3V (!!) which is slightly odd to say the least.

I've removed the IO board and it seems that pin 5 is being held at 3.3v by the DE10-nano, too. And, just to confirm, the lights on the nano itself are dancing wonderfully

I've run update_all in case something weird has happened on that front, but I'm scratching my head as to what could cause this now. Is my DE10 damaged somehow?

Any ideas gratefully received!

Out of desperation, I've even reimaged a new SD card with Mr Fusion... Same result, LEDs working on the DE10, nothing on the IO board. I've even checked with an LED (and resistor) on the LED header for the Power LED. Still nothing.

...I suspect I know what's happened here. During testing, I connected an LED directly between pins 1+2 of the External LED connector. With no current limiting resistor.

I presume that's then drawn too much current (or actually attempted to sink too much current) into the GPIO, which is GPIO_1_D4, connected to bank 4 of the Cyclone V SOC. The maximum current is can sink is 25mA, and without a current limiting resistor then it will have had more than that going into it, albeit briefly. (https://www.intel.com/content/www/us/en ... tings.html)

The LEDs on the Nano itself are connected to bank 5, which is completely different.

So, yes, I think I've damaged the cyclone V.

Lesson: don't connect LEDs without resistors to test things!

I updated my MiSTer recently after not touching it for a while, and the power/disk LEDs I'd wired up on my case (with resistors, no IO board) don't light up any more.

But it's core-specific. They still work with at least some cores, likely those that haven't had recent updates (ZX Spectrum Next and Pang 3 arcade were the first ones I've found)