Author Topic: Testing the PreenFM405 board  (Read 144 times)

sixbyseven

  • Team member
  • *
  • Posts: 4
    • View Profile
Testing the PreenFM405 board
« on: October 04, 2017, 06:40:56 PM »
Hi There,

I built my own Preen and Preen405 PCBs up, soldering all of the components including the SMT stuff. The STM32F4 was stupidly hard, you really need better than 10x magnification to do this properly. I don't and my vision even with a 6x magnifier is bad. Anyway, firmware loaded like a breeze... Everything works perfectly, except the MIDI RX. It connects to Ableton on USB, all the controls, menu, sounds work perfectly. Except the MIDI. I triple checked the wiring, Opto-isolator, diodes  everything. There is signal going through the opto-isolator, and to the pins on the 405, but it looks like pin 5 (according to the schematic) is where the RX signal hits the STM32.

I do not have probes that are small enough to test this pin, but does anyone know if there is a tool I can use with the ST-Link that can test all connected pins?

Sort of an in-place testing software.

Thank you.

Xavier

  • Administrator
  • Hero Member
  • *
  • Posts: 1235
    • View Profile
Re: Testing the PreenFM405 board
« Reply #1 on: October 04, 2017, 09:48:38 PM »
Hi,

Pusherman group ?  ;)
I have no idea how you solder the STM32F4... Congrats.
Would you post a picture of the preenF405 ?

To bad for the RX pins.
Sorry, I'm not aware of a tool that test connected pins.

You could configure the RX as a GPIO (remove the USART part).
https://github.com/Ixox/preenfm2/blob/master/src/PreenFM_init.c#L42
(I havent' looked at this part for a very long time....)
Read the value and display something when state changes.



Xavier

sixbyseven

  • Team member
  • *
  • Posts: 4
    • View Profile
Re: Testing the PreenFM405 board
« Reply #2 on: October 05, 2017, 03:55:34 AM »
All Fixed!!

I had a dickens of a time figuring out why pin 33 of the 405 and pin 6 of the OC1 were shorted to VCC. it turns out yet near pin 33 (pin 30 of the STM32), there is a VCC coupled pin (pin 32 of the STM32). I coated the area with more solder flux and retouched pin 33, 34 and 32 of the 405 and then retouched pins 30, 31, 32 on the STM32, and the short is now gone.

This synth works great, and is a ton of fun.

Attached are images of the PreenFM2 405 board and the area in question. The were shot with a cheap-assed camera microscope. The colour image is the entire board.

sixbyseven

  • Team member
  • *
  • Posts: 4
    • View Profile
Re: Testing the PreenFM405 board
« Reply #3 on: October 05, 2017, 03:56:31 AM »
Here is the colour image

Xavier

  • Administrator
  • Hero Member
  • *
  • Posts: 1235
    • View Profile
Re: Testing the PreenFM405 board
« Reply #4 on: October 06, 2017, 11:12:51 PM »

Impressive  8)
Thanks for the pictures
And glad to read it now works....