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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?
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.
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