Author Topic: Will PreenFM2 boot without the DAC?  (Read 174 times)

supreen

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Will PreenFM2 boot without the DAC?
« on: October 25, 2020, 03:51:01 AM »
Hi all. I'm building PreenFM2 from odd parts around the workshop and have the firmware flashed onto an old dev board which I've swapped the F405 onto. It's not booting past the bootloader though - wondering if it's due to not having the DAC connected yet. The 74hc165s are connected and appear to be working. I can navigate and have the firmware flashed again from a connected USB stick. If it should boot without the DAC I'd like to troubleshoot before building the DAC and output section.

Thanks!

Xavier

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Re: Will PreenFM2 boot without the DAC?
« Reply #1 on: October 25, 2020, 07:14:35 AM »

Hi,

Yes it should boot without DAC.
What firmware version do you use ?

> "an old dev board which I've swapped the F405 onto."
That's sounds a bit mysterious, what did you do exactly ?

Xavier

supreen

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Re: Will PreenFM2 boot without the DAC?
« Reply #2 on: October 25, 2020, 09:14:27 AM »
The board is a STM32F103RBT6 dev board (like a bigger blue pill) that I was given, with the f103 swapped for the f405 and the 2 capacitor pins lifted on the f405. I had the parts so I thought I'd give it a shot.

I suspected it should boot, so I will keep looking! I guess for some reason it thinks there's a button press happening during boot (as far as I can tell that's the only way to invoke the bootloader screen on boot). I'm using the latest firmware and bootloader, but have tried earlier versions of both.

Thanks Xavier - and thanks for all the work on this project and making it open source :-)
« Last Edit: October 25, 2020, 09:18:19 AM by supreen »

Xavier

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Re: Will PreenFM2 boot without the DAC?
« Reply #3 on: October 25, 2020, 11:54:10 AM »
The board is a STM32F103RBT6 dev board (like a bigger blue pill) that I was given, with the f103 swapped for the f405 and the 2 capacitor pins lifted on the f405. I had the parts so I thought I'd give it a shot.

Interesting. But you confirm it's a F405 on it and not a F103 ?
If you have the bootloader showing up at boot without pressing any button, yes that means the bootloader detects a pressed button and starts, instead of jumping to the firmware.
If you want to modify and recompile the bootloader you need the CS4344Rebased branch which is not yet merged in the master branch on github :
https://github.com/Ixox/preenfm2/commits/CS4344Rebased


Thanks Xavier - and thanks for all the work on this project and making it open source :-)

You're welcome  :)

supreen

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Re: Will PreenFM2 boot without the DAC?
« Reply #4 on: October 26, 2020, 12:03:49 AM »
But you confirm it's a F405 on it and not a F103 ?
If you have the bootloader showing up at boot without pressing any button, yes that means the bootloader detects a pressed button and starts, instead of jumping to the firmware.
If you want to modify and recompile the bootloader you need the CS4344Rebased branch which is not yet merged in the master branch on github :
https://github.com/Ixox/preenfm2/commits/CS4344Rebased


Yes it's a F405 - I got that much right at least ;-) I might replace it though as it was initially connected with the F405 VCAP pins not considered and they got 3.3v. So although the STM isn't dead, maybe it is not healthy.

I looked for the CS4344 version schematics but could not find them? Are they released?

Thanks for your time - much appreciated :-)