I've built three QDX units so far and they all work fine, but now I've hit a snag on #4.
Rev 3a PCB, I removed the short at the very beginning of the build.
Built for 9 Volts.
- Power-on with a 7.5 Volt current-limited bench power supply and it comes up in firmware update mode.
- Copy 1_08.QDX to the drive.
- Unmount, power-off.
- Power-on with a 7.5 Volt current-limited bench power supply and it draws about 170 ma, fast-flash LED, then steady-on.
- USB enumerates, then after a few seconds, it gets an error and disconnects.
- Does it with several PCs, using a hub and not using a hub.
We decide to do a firmware downgrade.
- Power-on/fast-flash/power-off.
- Power-on and I don't remember the flash-pattern, but a USB media device enumerates on Linux
- I copy 1_07.QDX to the drive.
- I remove 1_08.QDX from the drive.
- Power-off.
Now when I power-on, it only draws 90 ma and there are NO LEDs lit and no USB activity.
Is it possible to brick a QDX?
Anyone have a recovery procedure?
I've got several STM32 Discovery boards with the built-on debugger if that helps.
