Re: TS-7200 Cirrus A/D converter calibration

[Ken Hornstein <kenh%cmf.nrl.navy.mil@localhost>]

>You're talking to the Xilinx 9572 CPLD with those SPI calls to the 
>EEPROM (on the last page of the TS schematics).   It's the same on both 
>the TS-7200 and TS-7250.  The CPLD provides the glue logic needed to 
>access a lot of the functionality of the EP9302, such as a working 
>watchdog timer, ADC's, NAND flash and reset button handling.

Are you _sure_?  You're talking about U19, right?

I say this because I see no connections to the CPLD for the SPI bus.
Yes, the sample code on the web site does talk to the CPLD, but from
what I can see that's just to enable to chip select line to to EEPROM.
That seems to be U26, on the last page of the TS-7250 schematics.
There is no corresponding EEPROM I can find on the TS-7200 schematics.
Of course, I could be wrong.

>The built-in Cirrus ADC works, but I recommend the MAX197 ADC for 
>the TS-7200.  It handles larger (even bipolar) voltage inputs, has 
>programmable gain and is a lot less finnicky.  For one thing, with 
>the Cirrus ADC, you'll toast the entire ARM processor if you're 
>incautious with your analog inputs!

I have the MAX197, and I am going to use it.  But I wanted to explore
how hard it would be to get the on-board Cirrus ADC working.

(And if you have comments regarding an ADC kernel-to-userspace API,
like I posted about on current-users, I'd love to hear about it).

--Ken