On Wed, 1 Nov 2006, Per-Olof wrote:
> Then I might comment your answer. I have checked the ts website,
> www.embeddedarm.com, and they have demo code for the internal adc. If
> you are aware of the TS code for Optional mounted MAX 197, I would to be
> pleased for that link or information. What I found on TS page is: EP9301
> on-board A/D converter sample code
> <http://www.embeddedarm.com/downloads/samplecode/adc_72xx.tar.gz>
> (04-17-2006) however that does not help me in the end to get all 12
> bits of the external ADC.
Sorry but it's as simple as RTFM. It's in the ts7200 manual - "single
sample acquisition procedure" under the A/D Converter sections.
The same manual entry also says "The conversion result is now available
at locations 0x10C0_0000 (LSB) and 0x10C0_0001 (MSB). A single word read
at 0x10C0_0000 can also be used." Howver this is from the Preliminary
TS-7200 DRAFT manual. I bought my board within a month of so of
Technologics releasing the product, back in 2004.
Being essentially pragmatic, I coded as per the manual - got the results I
expected and have never checked the schematic in this area. However
schematics are produced by humans (there were faults in other areas), and
I believe Technologics do not claim the schematics is 100% complete - it
is there to give enough information to enable people to interface to the
product.
I would why you are so worried by it? Have you used code to read the
values and found that you didn't get 12bits? Maybe your code was wrong?
I suspect only Technologics staff can answer your specific
internals questions.
> And yes, I have read your code on your page. You maybe can explain how
> you get the complete 12 bits from the optional max197 with just one
> read, when the chip has only 8 bits ports with no HBEN. It the Cirrus
> EP93xx doing some stuff in between or anything that I missunderstood?
> You say in your code, adc_read that the value is: sv=*adc_io_read; where
> the address point at adc_io_read=(unsigned short *)IOMMAP(0x10c00000).
> However reading this once would give the 8 bit of max197? The difference
> is that the internal ADC is possible to have all 12 bits read when it is
> interfaced.
>
> So question remains, what is done with HBEN on the external mouted
> MAX197, to get all 12 bits?
>
>
> /PO
>
>
> Jim Jackson wrote:
>
> >On Tue, 31 Oct 2006, Per-Olof wrote:
> >
> >
> >
> >>Hello,
> >>
> >>I have concerns how to use all the 12 bits on the MAX197 ADC on TS-7200.
> >>According to the schematics the HBEN is not connected to any port or
> >>function, and terefore it would not be possible to select to bit 8..11
> >>form the conversion. Either I can't find any register or writing to
> >>MAX197 that would enable the uppber bits.
> >>Is it possible to use all 12 bits, or is the board just printed for 8
> >>bit (and 8 channel)?
> >>
> >>
> >
> >I thought Technologics had put out some demo code for accessing the
> >MAX197 on a ts7200???? Have you checked all the docs?
> >
> >As I've recently said on another thread on the MAX197 - you can check
> >out my adc_logger and adio software referenced from my ts7200 webpage.
> >
> >Jim
> >
> >----------------------------------------------------------------------------
> >HomePage: http://www.comp.leeds.ac.uk/jj
> >TS7200 Page: http://www.comp.leeds.ac.uk/jj/linux/arm-sbc.html
> >
> >
>
>
>
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