pin2dmd does not work without PC USB :-(

[matiou]

Hello all, I need help!

So I just assembled my first pin2dmd... shield v4 and nucleo 144.

But it refuses to work if I don't have the USB port "CN1" connected to a PC... Which is a bit frustrating!

config:
- last version of firmware flashed (v2.j36.m26), latest pinDMD installed
- no USB cable is plugged in
- the shield is connected to 5V 5 amps via the screw terminals
- JP3 is on E5V
- an SD card is inserted

If I turn on the 5V power supply, the green led from the shield turns on, the small green led "PWR" from the nucleo turns on, but the red led "LD4" from the nucleo blinks red and... nothing shows up on my LCD panels.

As soon as I plug an USB cable from a PC in the "USB PWR" connector, the red led stops blinking, stays red and ta da... my panels turn on with a nice "PIN2DMD" logo. Then, if I unplug the USB cable, things keep working. If I turn off the 5V and turn back on, it does not work...

Populating JP1 or not does not seem to change anything... Connecting a phone charger instead of a computer to inject 5V in the micro USB CN1 does not work...

Weird, no ?
Any idea ?

 

[lucky1]

Did you try without SD-card ?

Did you try a older version of the ST-Link firmware ? 

https://www.st.com/en/development-tools/stsw-link007.html

I have V2.J32.M22 .

 

[matiou]

Older firmware fixed it! YES!

Thanks lucky! 

I guess it's not always good to be completely up to date ?

I wish I had tried that earlier, I spend 2 or 3 hours troubleshooting!
- I reflashed the firmware 2 times (but always latest version)
- I reflowed suspicious solder joins on my shield
- I read 5 times the meaning of all jumpers on the nucleo
- I read forums about people having problems powering up the nucleo
- I rewired all, just with dupont wires to remove the shield from the picture
AND ONLY then I tried an older firmware... and it worked!

Thanks again lucky for a super quick reply.