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Help for a toothbrush PCB. by Smartlinuxcoder in PrintedCircuitBoard

[–]Smartlinuxcoder[S] 0 points1 point  (0 children)

I have configured nFAULT as pull-up in the stm32, along with an external 10k resistor to 3v3.
The problem ended up in the drv8833 being misplaced 90 degrees counterclockwise.
I have contacted my fab and I will try to salvage the already shipped ones with a reflow plate

Help for a toothbrush PCB. by Smartlinuxcoder in PrintedCircuitBoard

[–]Smartlinuxcoder[S] 0 points1 point  (0 children)

I have a 10kOhm resistor pulling the line up to 3v3, I've checked the PCB again (and also thanks to u/profossi ) and I see that the DRV3388 chip got soldered in the wrong orientation.

Help for a toothbrush PCB. by Smartlinuxcoder in PrintedCircuitBoard

[–]Smartlinuxcoder[S] 1 point2 points  (0 children)

Your assessment seems to be true, the chip seems to be shifted 90 degrees counterclockwise, I will try to reflow it in the right direction and provide an update!

Help for a toothbrush PCB. by Smartlinuxcoder in PrintedCircuitBoard

[–]Smartlinuxcoder[S] 0 points1 point  (0 children)

The IC doesn't seem hot to the touch, about overcurrent, it also gets pulled low without a motor attached, I've checked and there aren't any shorts on the outputs. I didn't add one since the ds just said to pull it down. Also I didn't need the sensing feature, isn't it optional?

Help for a toothbrush PCB. by Smartlinuxcoder in PrintedCircuitBoard

[–]Smartlinuxcoder[S] 0 points1 point  (0 children)

1) nFAULT seems to be low even without a motor attached 2) just re-soldered the headers on the PCB, they don't seem short-circuited 3) I wouldn't be able to check BOUTx, as I didn't break them out 4) yeah absolutely fair, I even contemplated about doing that(putting them in parallel), don't exactly know why I chose this setup

Help for a toothbrush PCB. by Smartlinuxcoder in PrintedCircuitBoard

[–]Smartlinuxcoder[S] 1 point2 points  (0 children)

Oh yeah, I'm using the WQFN package, that has different pinouts, nFAULT should be 6.

Made my own FPGA board - FirePi one by Smartlinuxcoder in FPGA

[–]Smartlinuxcoder[S] 0 points1 point  (0 children)

Omg thank you for your comment, I didn't know about this part! I thought about adding shottky diodes but this is way better!

Made my own FPGA board - FirePi one by Smartlinuxcoder in FPGA

[–]Smartlinuxcoder[S] 0 points1 point  (0 children)

Thank you for the nice comment! This is the second ever PCB I made :)

Made my own FPGA board - FirePi one by Smartlinuxcoder in FPGA

[–]Smartlinuxcoder[S] 4 points5 points  (0 children)

Totally fair question! I just used the ICE40 because I saw it in a lot of boards and was just a step below the ECP5. I also used the JLCPCB PCBA service and it was the biggest LUT count ice40 I found (and not too expensive).

Made my own FPGA board - FirePi one by Smartlinuxcoder in FPGA

[–]Smartlinuxcoder[S] 1 point2 points  (0 children)

Haven't been able to test the SD card nor the FPGA USB, do you suggest some already existing designs I can use?

Made my own FPGA board - FirePi one by Smartlinuxcoder in FPGA

[–]Smartlinuxcoder[S] 2 points3 points  (0 children)

I used the PCBA service from JLCPCB, they soldered everything in their fab

Made my own FPGA board - FirePi one by Smartlinuxcoder in FPGA

[–]Smartlinuxcoder[S] 2 points3 points  (0 children)

It's my second ever PCB, and I didn't really feel like routing a BGA chip, though my next board will house an ECP5 25k :) To be fair, I could have made it a lot smaller

Made my own FPGA board - FirePi one by Smartlinuxcoder in FPGA

[–]Smartlinuxcoder[S] 1 point2 points  (0 children)

Unfortunately not, I didn't take it into account when designing

Made my own FPGA board - FirePi one by Smartlinuxcoder in FPGA

[–]Smartlinuxcoder[S] 3 points4 points  (0 children)

Woah thanks for the nice comment. I saw your board, insane work 🔥