Title: Strange behavior
Post by: WD8BXS on 08. March 2021, 15:53:46
I have an OV140 board here I am working on, and the bias voltage pin 8 on 30 pin header is working backward.
High voltage at low bias setting in menu, and low voltage as it goes upward.
Any ideas?
TNX,
Chuck WD8BXS
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Title: Re:Strange behavior
Post by: WD8BXS on 11. March 2021, 01:56:40
Title: Re:Strange behavior
Post by: DB4PLE on 11. March 2021, 11:46:17
Hi Chuck,
have you checked the DAC output from UI board to RF board: I assume this still goes in the correct direction (higher bias value, higher voltage).
If so, it is strange indeed but is somewhere in the "analog" part of the bias generation. And then I can't really help. If, however, the bias control voltage from STM itself does weird things, I may be the right person to look into this.
73
Danilo |
Title: Re:Strange behavior
Post by: SP3OSJ on 11. March 2021, 17:44:35
Hi
Check connection of pin 8 (30pin) <-> pin 41 (STM)
Check if there is no connection between pin 40<-> pin 41 (STM)
Check if there is no connection between pin 42<-> pin 41 (STM)
73
Artur |
Title: Re:Strange behavior
Post by: WD8BXS on 12. March 2021, 14:39:28
Thanks , I will check this out later today!
Chuck |
Title: Re:Strange behavior
Post by: WD8BXS on 12. March 2021, 16:59:39
Hi Danilo,
The DAC is working backward!
When bias setting is o, DAC is 2.4 volts.
When bias is 100, DAC is .4 volts
Thanks,
Chuck |
Title: Re:Strange behavior
Post by: DB4PLE on 12. March 2021, 17:11:42
Ok,
very interesting!
Now I would like to learn which firmware version is loaded and if it was loaded from the "official" download archive run by Andreas (https://www.amateurfunk-sulingen.de/uhsdr/firmware-latest/).
Honestly, I cannot explain why the software does this suddenly backwards, but if this is an official firmware build, we can easily check if it does the same thing on other machines. Then we have to fix the software. If it only happens on the particular machine, it is most likely a hardware issue, but probably closer to the UI / MCU side of things than to the actual RF board circuit. E.g. it is worthwhile to follow Arturs suggestion to check the surroundings of the DAC pin on the MCU and follow the path of the DAC signal to the pin header.
73
Danilo |
Title: Re:Strange behavior
Post by: SP3OSJ on 12. March 2021, 19:34:11
These are simple faults to diagnose:
Look screen: |
Title: Re:Strange behavior
Post by: WD8BXS on 13. March 2021, 11:49:56
Good Morning,
Here is what I have.
I am unclear about the difference in F7 or H7!
Maybe I used the wrong one?? |
Title: Re:Strange behavior
Post by: WD8BXS on 13. March 2021, 11:50:26
Title: Re:Strange behavior
Post by: DB4PLE on 13. March 2021, 12:14:49
Hi Chuck,
please update to 2.12.0 before doing any further search for hardware issues. See link in my last message or go straight here: https://www.amateurfunk-sulingen.de/uhsdr/firmware-latest/OVI40/F7/
We fixed serious issue with the release 12.2.0. It was specific to the STM32F7xx processor firmware builds (i.e. it was not affecting STM32H7xx or STM32F4). This issue may cause strange behavior as it produces random content in some areas of the memory, so we cannot really say what it does on an individual TRX and it could be that what you are seeing is caused by this. So give it a try. This issue was present in all STM32F7 firmware we ever released. Only 2.12.0 solves this.
73
Danilo
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Title: Re:Strange behavior
Post by: WD8BXS on 13. March 2021, 12:42:38
OK, Thanks,
I will get to it a little later today!
TNX Chuck |
Title: Re:Strange behavior
Post by: WD8BXS on 13. March 2021, 14:48:06
I have just updated to the new firmware.
I still have the same result, DAC still working backwards.
I am still unclear about the difference of F7 or H7.
I used F7 on this one.
Thanks,
Chuck |
Title: Re:Strange behavior
Post by: DB4PLE on 13. March 2021, 14:58:06
Hi Chuck,
STM32F7xx and STM32H7xx (or F7 / H7 for short) are different processor families from ST Microelectronic. They are very similar (e.g. have the same pinout, that's why the OVI40 UI runs with both) but they are not identical. Firmware for H7 does not work on F7 and vice versa, hence we have 2 different binaries.
I will look into the DAC issue.
73
Danilo
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Title: Re:Strange behavior
Post by: DB4PLE on 13. March 2021, 15:34:30
Hi Chuck,
what is the Bias DAC output if RX is active (normally there should be 0V at the DAC pin).
73
Danilo |
Title: Re:Strange behavior
Post by: SP3OSJ on 13. March 2021, 17:16:06
Here is the path torn out.
PWM there is no GND. |
Title: Re:Strange behavior
Post by: WD8BXS on 13. March 2021, 18:03:38
I am showing 1.49v on receive
Chuck |
Title: Re:Strange behavior
Post by: WD8BXS on 13. March 2021, 18:06:54
Artur, I do not understand what you are showing me!!
Chuck |
Title: Re:Strange behavior
Post by: DB4PLE on 13. March 2021, 18:16:08
Hi Chuck,
Side note: I think Artur wants to point out some strange looking area where the solder mask is scratched. That can lead to problems. I haven't looked up which pins these are but it indeed is something which normally looks better.
But now to the point: I am pretty sure, it is a hardware issue. And to finally verify, please remove R83 on the RF board, just as Artur suggested. And repeat the measurements at header pin 8 (RX, TX bias low, bias high value). If it still goes the wrong direction, well, the problem is between R83 and the processor or even in the processor (damaged DAC). If the removal corrects the voltage direction on pin 8, the problem is on the RF board, potentially U18 is damaged.
73
Danilo |
Title: Re:Strange behavior
Post by: WD8BXS on 13. March 2021, 18:20:05
| WOW, with R83 removed, I have in excess of 3v at DAC on receive.... |
Title: Re:Strange behavior
Post by: WD8BXS on 13. March 2021, 18:28:31
I got this one in for repairs.
The user had broken the Step button off and tried to use tweezers to press the button.
The thing went dead.
I sued Stlink to revive it.
Now there is this issue!!
Thanks,
Chuck |
Title: Re:Strange behavior
Post by: WD8BXS on 13. March 2021, 18:41:28
OK, I have just taken the RF board from my radio and hooked it to the OV140
I am still getting the same results, Dac goes backward.
Chuck |
Title: Re:Strange behavior
Post by: DB4PLE on 13. March 2021, 18:43:17
Hi Chuck,
than I have good and bad news for you and the owner:
Most likely the processor has been damaged. Has happened before (I ruined 2 processors along the way. Most often it only affects few pins but then nothing can be done for these anymore). Only option is then to replace the processor.
That was the bad part. The good part comes now: go for a STM32H743 or STM32H753 instead when replacing. Much faster, less power hungry.
73
Danilo
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Title: Re:Strange behavior
Post by: DB4PLE on 13. March 2021, 18:50:27
Hi Chuck,
maybe you have some luck: I checked the schematics and PA5 is the DAC we have been looking at. But next to it (pin 41) is on pin 40 PA4 which is the volume DAC. Please see if changing the volume (AFG) has an impact on the measure value (or if there is a short between 40 and 41).
73
Danilo |
Title: Re:Strange behavior
Post by: WD8BXS on 13. March 2021, 18:59:58
Hi Danilo,
Changing the volume has no effect.
I do have a new MCU here but it is also the F7.
I will change it out.
Chuck |
Title: Re:Strange behavior
Post by: WD8BXS on 13. March 2021, 20:37:06
Installed new MCU.
Bootloader and firmware loaded via dfuse
When I hit power, I just get white screen.
Let go of power screen goes blank
I don't think the MCU is starting. I have voltage until I let go of the power button.
Back to the drawing board!!!
Chuck |
Title: Re:Strange behavior
Post by: WD8BXS on 14. March 2021, 18:19:27
All MCU pins seem OK
Will keep looking |
Title: Re:Strange behavior
Post by: DB4PLE on 14. March 2021, 18:27:17
Hi Chuck,
voltage goes away when letting go of the power button -> bootloader is not starting. Making sure power is not going away is one of the first things the bootloader does after early startup.
As the bootloader really does not have many requirements, it can also be that the processor is not configured as it should be.
For checking / fixing this, you need a ST Link and the STM32 Link program installed. Do a Chip Erase with STM32 Link, that brings everything to a default state. We have had the case that brand new MCU needed this as it seems you can get them also in other configurations from STM.
If you need more detailed instructions, just let us know.
73
Danilo |
Title: Re:Strange behavior
Post by: WD8BXS on 14. March 2021, 19:44:30
Hello Danilo,
Just finished mass erase and Option byte settings.
Loaded bootloader and firmware with dFuse.
Same results, white screen while holding power button.
SOOO Frustrating.
de CHuck |
Title: Re:Strange behavior
Post by: DB4PLE on 14. March 2021, 19:47:22
Hi Chuck,
indeed. Not much we can do for you now, except keeping the fingers crossed and wishing you good luck. It should be nothing more or less than a solder bridge or a bad solder joint. You only have 144 to check :'(
73
Danilo |
Title: Re:Strange behavior
Post by: WD8BXS on 14. March 2021, 19:49:27
Yes, I have checked them 4 times, I do not find any issues.
Time to walk away
Chuck |
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