After DRV Swap "No Firmware Read Response" No Flashing Red LED at powerup

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Acidfie
Posts: 3
Joined: 22 May 2017, 18:11
Location: Aalen

After DRV Swap "No Firmware Read Response" No Flashing Red LED at powerup

Postby Acidfie » 22 May 2017, 18:19

Hello there guys,

i have a little problem with my VESC. It once worked until i fucked up the DRV with the current ramp step bug for OS X.

I could connect it but the red led flashed 3 times when i wanted to start the motor detection. So i went to my university and had the DRV replaced with a SMC rework station, but since i did this, it cant be connected to my laptop. "NO FIRMWARE READ RESPONSE".

I tried it with a lab-current source with 15V, nothing. No flashing 3x Red LED at power up/connecting to power. no amps drawn. nothing.

So i checked the voltage at the tc2117. with gnd and 1. pin nothing. 2. pin 0,17V and 3. pin only 1V.

C31 and C33 had no short. So do i need to reflash the firmware or is the exposed pad on the drv8302 not soldered correct on the board?

are there anymore things that could be with the board?

best regards, robin

rew
Posts: 904
Joined: 25 Mar 2016, 12:29
Location: Delft, Netherlands.

Re: After DRV Swap "No Firmware Read Response" No Flashing Red LED at powerup

Postby rew » 23 May 2017, 05:38

The exposed pad on the DRV is very important. It is the ground pin for the chip. There is no other ground. If you do not connect that ground, the DCDC part of the DRV chip will THINK that it ground is at say 5V and then try to make 5V above that level. This will ruin your day.
Similarly, with the ground level of the DRV chip above 3.3V, it will source current into the CPU. This will kill the CPU quite fast.

On official VESCs there is a zener diode on the 5V to prevent excessive voltages there. But I'm not sure how long that is able to work before things break down anyway....

Acidfie
Posts: 3
Joined: 22 May 2017, 18:11
Location: Aalen

Re: After DRV Swap "No Firmware Read Response" No Flashing Red LED at powerup

Postby Acidfie » 23 May 2017, 08:21

So i will try again to solder the Exposed Pad on the GND, think it didnt work out properly..

rew
Posts: 904
Joined: 25 Mar 2016, 12:29
Location: Delft, Netherlands.

Re: After DRV Swap "No Firmware Read Response" No Flashing Red LED at powerup

Postby rew » 23 May 2017, 20:20

It MAY be too late for that. This is one of those things where one mistake smokes a bunch of other stuff....

Acidfie
Posts: 3
Joined: 22 May 2017, 18:11
Location: Aalen

Re: After DRV Swap "No Firmware Read Response" No Flashing Red LED at powerup

Postby Acidfie » 24 May 2017, 10:22

Is the VESC now dead? or is it repairable?

arvidb
Posts: 206
Joined: 26 Dec 2015, 14:38
Location: Sweden, Stockholm

Re: After DRV Swap "No Firmware Read Response" No Flashing Red LED at powerup

Postby arvidb » 24 May 2017, 21:14

Of course it is repairable - the question is how many components you will have to replace. And noone here can answer that question for you. You will need to do some trouble shooting. I would start by bringing the power rails back on line (+5 V and then +3.3 V). The +5 V is generated by the DRV chip's switching regulator.

Then, if you get no blinks from your VESC even though the 3.3 V is online, you'll probably have to replace the CPU. And so forth and so on until everything seems to work alright.

rew
Posts: 904
Joined: 25 Mar 2016, 12:29
Location: Delft, Netherlands.

Re: After DRV Swap "No Firmware Read Response" No Flashing Red LED at powerup

Postby rew » 25 May 2017, 04:23

My power-stage separated from the controller-board. If that happens with the power off, nothing happens. If it happens instantaneously, nothing happens. But of course it doesn't. This seems to apply unhealthy voltages to part of the controller board, so I now have a fried controller board. I Have the impression that some measurements are no longer working. It does something but not much. For now I've replaced the board.


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