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Firmware bug?

gamma3, gamma24 (plug-in for the γ3)

Re: Firmware bug?

Postby cobretti » January 25th, 2017, 12:59 pm

amb wrote:Hmm, I don't see anything in the code where this could happen. Normally, on an LCD, the backlight is faded down to full dark and everything on screen should become so. I note that you're using a VFD which is not supported. Maybe there is a problem with the code with this type of display. I'll have to dig further.

Is this problem intermittent or is it consistently reproducible? If the latter, what steps you need to go through to get it to happen?

The problem is reproductible. When streaming through USB using my laptop, if I move the track time slider in Foobar2000 to somewhere in the middle, the sampling frequency appear on the display. It doesn't always happen on the first trial, but it happens when music start from low levels and I move the slider to somewhere where music is louder, then it appears. I would say it happens once out of 7-10 trials like that. The Atmel (or something else) gets fooled. Weird. It passes through USB streaming data and it causes this message.
When display is turned to ON or auto, no problems.
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Re: Firmware bug?

Postby cobretti » January 25th, 2017, 1:58 pm

My theory is that when I move the time slider bar on the Foobar2000, the ζ1 loses the sampling frequency info for a split of a second, and then when it gets back on track the GPIO send either LO or HIGH to Atmega328P, and it shows up on the display.
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Firmware bug?

Postby amb » January 25th, 2017, 5:20 pm

The sample rate display is calculated by the γ3 firmware based on the SRC ratio as read via I2C from the SRC4392. If the calculated rate isn't a valid multiple of 44.1KHz or 48KHz then a blank sample rate is shown. The ζ1 is not involved in this at all.

But anyway, I can't see how only that portion of the display would light up rather than the whole screen.
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Re: Firmware bug?

Postby cobretti » January 26th, 2017, 1:01 pm

Well, I don't know either. So what are the possibilities here? Corupted I2C data?
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Re: Firmware bug?

Postby amb » January 26th, 2017, 1:07 pm

No, because corrupted I2C data would lead to a blank sample rate display, not anything valid. Also corrupted data should not cause only a portion of the screen to light up. The whole display dimmed or restored at once. If you have a LCD instead of VFD, try to see if the same problem could be reproduced on the LCD.
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Re: Firmware bug?

Postby cobretti » January 26th, 2017, 2:18 pm

OK, I can do that.
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Re: Firmware bug?

Postby cobretti » February 11th, 2017, 2:47 pm

New discovery. The bug won't show up when used on coaxial S/PDIF input 1. It appears only when USB is being used. I wonder if one of the isolators could be compromised.
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Re: Firmware bug?

Postby cobretti » February 25th, 2017, 9:00 am

OK, I swapped the display and put the approved LCD. Yes, it happens with LCD as well. I checked everything with scope and could not find anything suspicious. Checked and reflowed all joints on y24, didn't find anything either. Any thoughts?
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Re: Firmware bug?

Postby cobretti » February 25th, 2017, 9:02 am

cobretti wrote:New discovery. The bug won't show up when used on coaxial S/PDIF input 1. It appears only when USB is being used. I wonder if one of the isolators could be compromised.

I was wrong on this one. It will happen on S/PDIF as well, just takes longer.
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Re: Firmware bug?

Postby amb » February 25th, 2017, 11:38 am

Hmm. The problem seems to be on your γ24 board. I don't know how it would behave that way, but is there anyone near you who has a properly working γ3? An easy test would be to swap the γ24s between the two and see if the problem moves from one unit to the other, or if it stays on the same unit.
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