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56F807 DSP failures

Started by Bende Georg July 6, 2004
Hello all,

Recently we have started some test production, and on about 1% of the units
claimed to be defective by our test software. I took a closer look on these
units and I have noticed a huge offset on 1 or 2 of the ADC channels. At 0V
level it showed the same value as the other -good- ones at 1V, while the whole
measuring range is calibrated to 3V. Did anyone meet such a symptom before? Is
it a typical DSP fault or some kind of design flaw? I have checked all voltages
corresponding to the analog inputs such as Vdda and Vssa and their values are
OK.

Any suggestions and ideas are welcome,
Georg Bende
Softwareentwickler
Abteilung Elektronik
Dr. Fritz Faulhaber GmbH & Co KG
Daimlerstr. 23
71101 Schaich
Tel: +49 7031 638294




Could your problem be related to the ettara issue of the ADCs not working below a 24mV? 
 
Personally, I think this is something Motorola needs to fix, and if I had known about the problems before I started development I would not be using these chips today.  I'm using the 803 and I think they are on Rev F Silicone and still have not fixed the problem.  I know the next time I choose a chip it may not be Motorola because of this lingering issue.
 
I've seen that microchip has a new 16-bit dsp out....
 
Jacob
 


From: Bende Georg [mailto:g...@faulhaber.de]
Sent: Tuesday, July 06, 2004 3:05 AM
To: m...@yahoogroups.com
Subject: [motoroladsp] 56F807 DSP failures

Hello all,

Recently we have started some test production, and on about 1% of the units claimed to be defective by our test software. I took a closer look on these units and I have noticed a huge offset on 1 or 2 of the ADC channels. At 0V level it showed the same value as the other -good- ones at 1V, while the whole measuring range is calibrated to 3V. Did anyone meet such a symptom before? Is it a typical DSP fault or some kind of design flaw? I have checked all voltages corresponding to the analog inputs such as Vdda and Vssa and their values are OK.

Any suggestions and ideas are welcome,
Georg Bende
Softwareentwickler
Abteilung Elektronik
Dr. Fritz Faulhaber GmbH & Co KG
Daimlerstr. 23
71101 Schaich
Tel: +49 7031 638294


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We have used the 807 in several high volume products and have not noticed any A/D problems relating to the processor.
 
We did have some minor issue on our part due to boards being calibrated with a different power supply than used in the field (and off by a tenth of a volt or so) , resulting in slight calibration error until we realized the problem.
 
Howard
-----Original Message-----
From: Bende Georg [mailto:g...@faulhaber.de]
Sent: Tuesday, July 06, 2004 6:05 AM
To: m...@yahoogroups.com
Subject: [motoroladsp] 56F807 DSP failures

Hello all,

Recently we have started some test production, and on about 1% of the units claimed to be defective by our test software. I took a closer look on these units and I have noticed a huge offset on 1 or 2 of the ADC channels. At 0V level it showed the same value as the other -good- ones at 1V, while the whole measuring range is calibrated to 3V. Did anyone meet such a symptom before? Is it a typical DSP fault or some kind of design flaw? I have checked all voltages corresponding to the analog inputs such as Vdda and Vssa and their values are OK.

Any suggestions and ideas are welcome,
Georg Bende
Softwareentwickler
Abteilung Elektronik
Dr. Fritz Faulhaber GmbH & Co KG
Daimlerstr. 23
71101 Schaich
Tel: +49 7031 638294


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Nachricht
The problem I mentioned does not sound like your problem.
 
We havn't had any 807 issues from our experience. One minor problem that I can recall was that we had to use 4 Wait States (WS) for our external SRAM because of the impossibly tight requirements for the timing spec combined with poor WS granularity (0/4/8/12WS supported). With 0WS, it worked on most units, but failed (usually at high temperature) on a small percentage of chips. We got around this by keeping critical stuff in internal SRAM.
 
Howard
-----Original Message-----
From: Bende Georg [mailto:g...@faulhaber.de]
Sent: Tuesday, July 06, 2004 11:03 AM
To: Ebersman, Howard
Cc: m...@yahoogroups.com
Subject: AW: [motoroladsp] 56F807 DSP failures

Hello Howard,
 
We use the same supply voltage for the tests; there is normally some variation in the uncalibrated ADC readouts, up to 2-3 LSB I can handle it. But this seems like a "stuck" bit - I can't explain it any other way. Did you ever have such a problem?
Another question if you have high-volume product experiences: what were the most frequent errors regarding to the DSP? There was a discussion whether we should make a flash/RAM R/W test, does it make any sense? Our product is has to be tested as thoroughly as possible, but I would rather abandon the senseless tests....
 
Georg Bende
Softwareentwickler
Abteilung Elektronik
Dr. Fritz Faulhaber GmbH & Co KG
Daimlerstr. 23
71101 Schaich
Tel: +49 7031 638294
-----Ursprgliche Nachricht-----
Von: Ebersman, Howard [mailto:H...@microwavedata.com]
Gesendet: Dienstag, 6. Juli 2004 16:50
An: Bende Georg; m...@yahoogroups.com
Betreff: RE: [motoroladsp] 56F807 DSP failures

We have used the 807 in several high volume products and have not noticed any A/D problems relating to the processor.
 
We did have some minor issue on our part due to boards being calibrated with a different power supply than used in the field (and off by a tenth of a volt or so) , resulting in slight calibration error until we realized the problem.
 
Howard
-----Original Message-----
From: Bende Georg [mailto:g...@faulhaber.de]
Sent: Tuesday, July 06, 2004 6:05 AM
To: m...@yahoogroups.com
Subject: [motoroladsp] 56F807 DSP failures

Hello all,

Recently we have started some test production, and on about 1% of the units claimed to be defective by our test software. I took a closer look on these units and I have noticed a huge offset on 1 or 2 of the ADC channels. At 0V level it showed the same value as the other -good- ones at 1V, while the whole measuring range is calibrated to 3V. Did anyone meet such a symptom before? Is it a typical DSP fault or some kind of design flaw? I have checked all voltages corresponding to the analog inputs such as Vdda and Vssa and their values are OK.

Any suggestions and ideas are welcome,
Georg Bende
Softwareentwickler
Abteilung Elektronik
Dr. Fritz Faulhaber GmbH & Co KG
Daimlerstr. 23
71101 Schaich
Tel: +49 7031 638294


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Hello all,
 
I am wroking on 56F801 and am very much new to DSP itself.
 
I have been trying to modulate certain signal through FSK.
 
And ,I am not able to figure out the register which I need to set to get the required sampling frequency.
Can anyone help me on this..???
 
Thanking you,
 
Mrugesh.


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