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HW 4.12 USB Device Descriptor Failed-> Red light flashed on start

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MTBVASEY
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HW 4.12 USB Device Descriptor Failed-> Red light flashed on start

Hi all,

I'm after some advice after spending too long trying to fault find on two VESC 4.12 boards I've soldered myself. The PCB are similar to https://www.diygadget.com/electric-skateboard-parts/176-vesc-bldc-open-source-electric-skateboard-esc-partially-assembled.html, but i purchased from eBay.

I am able to load bootstrap using the ST Link and the utility software, I have loaded various .hex and .bin files I've found for the 4.12 HW standard but none seem to work. The latest I have loaded is from the firmware folder for the BLDC tool which has default in the label.

When I power the VESC from a bench top PSU (@15V, drawing 0.02A) the blue LED comes straight on, followed by the red flashing three times, then finished up with the green LED illuminating. My PC then detects that a device has been connected, but then fails to load the device driver. I have tried to manually assign a driver, but I can't seem to find the STM VCP driver from the list provided.

If the PC detects the VESC, then I assume that the two USB coms lines are being pulled high, but then the VESC doesn't appear to be responding to the PC correctly.(both VESCs do exactly the same) The resistance from the USB pins to the D+(44) and D-(45) are both 22R , and are not shorted together. 

I am hoping this is something I'm doing daft, but I have replaced the STM32F4 on both boards twice, and also repalaced the DRV for both in case this was causing an issue. I have confirmed the 5V and 3.3V rails are present and the oscillator for the USB to function is clocking at 8MHz as required.

Any help would be much appreciated, kind regards, Andy.

MTBVASEY
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Joined: 2018-04-04 10:38
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Maybe I spoke too soon. I had brought the wrong usb connectors!!! Managed to use the unused terminal on the connector and link to the 22R resister, then cut a USB cable up and swapped the positive and negative cables over!

In hindsight, the ST LINK kept depowering when I connected the VESC via USB. Turns out I was shorting the USB power! Oops.

Alls good now though, and its been quite a learning experience! :-)

Thanks for looking, Andy. 

MTBVASEY
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Last seen: 4 years 2 months ago
Joined: 2018-04-04 10:38
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Hey,

I thought I had it all figured out, but I'm still having troubles...

On the one VESC, the red LED flashes three times on start up. The BLDC tool attaches fine, but then the motor detection fails. When I run up the motor, it will spin for slower speeds, then it'll suddenly stop, with the red LED flashing and a DRV failure reported in the BLDC tool.

The other VESCs red LED does not flash on start up, but does connect to the BLDC tool and does illuminate the green LED. It also becomes brighter when i increase the demand (it passes the demand across the CAN connection to the other VESC). The motor doesn't appear to even try to spin, and also fails the motor detection.

I think I'm going to replace the DRVs on both boards, is this the correct/best next step?

Your help would be much appreciated.