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[SOLVED] Focus motors not working


Dan Walker
 

Hi All,

I while back I posted about not being able to get anything working with the focus motors.

I found that the voltage on the 1A, 1B, 2A, 2B pins of  the drivers (in this case a4988, but TMC2208 also didn't work) was only 4V and not the 12V of the Vmot.

I also learned that the voltage on the SLEEP and RST pins was 1.4V, which is below the threshold for the high state (2.1V). So essentially the drivers we sleeping.

I was sure that I have a dodgy connection somewhere, but with loads of searching I cannot find it, so I soldered a pullup resistor from 3V3 to the SLEEP pin and it works :)


Photo, shows how I got it working. (Don't judge the terrible soldering!) I might relegate the board to a bench development board and do one up properly not I know what I'm doing a bit more.

Just happy that I got it working, but still don't know why the SLEEP and RST pins were 1.4V and not >2.1V as they should have been. There is no other connection to them!

Thanks,

Dan


Howard Dutton
 

On Tue, Oct 20, 2020 at 04:16 AM, Dan Walker wrote:
I was sure that I have a dodgy connection somewhere, but with loads of searching I cannot find it, so I soldered a pullup resistor from 3V3 to the SLEEP pin and it works :)
Whatever works, but the SLP/RST is a commonly used step-stick socket design:

https://a.pololu-files.com/picture/0J10073.600.jpg?75d9ca5bb2e095e5c5f64350019e1b81
https://www.pololu.com/product/1182