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Re: TS-7200 Cirrus A/D converter calibration



Ken Hornstein wrote:
So, according to the TS-7200 manual, the built-in EP93xx A/D converters
have been calibrated at the factory and calibration values have been
written to the EEPROM.  Okay, fine.  But the question I have is ...
where is this EEPROM?

I downloaded the sample code provided by TS, and that code mentions the
TS-7250.  From looking at that code and pouring over the EP9301 manual,
I am guessing that on the TS-7250 the EEPROM is a serial EEPROM and it's
available on the SPI bus.  A look at the TS-7250 schematic confirms this.
But ... I cannot find a comparable EEPROM on the TS-7200 schematic.  This
leads me to three possible conclusions:

- There are no calibration values and the documentation is wrong.
- There are calibration values and they're in the same place as on the
  TS-7250, I just missed them.
- There are calibration values, but they are hidden somewhere else.

Anyone have any idea what the correct answer is?

--Ken


We only started calibrating on the TS7250 and newer products. IIRC, theres only a couple of the ep93xx ADC channels brought out on the TS-7200 because at the time the TS-7200 was released (2004) the current silicon of the EP9302 CPU had some errata dealing with internal ADCs. On the TS-7200 we did create an option for connecting a Maxim 197 ADC chip, but you're right there is no EEPROM on the TS-7200 to store calibration values so we didn't there. It was the internal ADC's that needed the calibration though, the MAX197 on the TS-7200 is actually pretty good by itself.

//Jesse Off


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