>
> Hi TJF,
>

It is not the impedance I think, but it was interesting to go back to the 
normal io example 1.c. The behaviour is different. Output when using that 
example (but without leftshift):

    0    0    0    0    0    0    0    0
  C37   13  9B7    5  199  E34    0  1A4
  C3B   13  9B7    5  199  E36    0  1A5
  C37   12  9BD    5  197  E36    0  1A4
  C37   11  9B8    5  199  E34    0  1A5
  C38   13  9B7    5  199  E36    0  1A5
  C37   13  9BA    4  197  E35    0  1A5
  C37   12  9BA    4  197  E35    0  1A5
  C37   12  9B7    4  197  E35    0  1A5
  C37   12  9B7    5  197  E35    0  1A5
  C37   12  9B7    5  197  E35    0  1A5
  C37   12  9B7    5  197  E35    0  1A5
  C37   12  9B7    5  197  E35    0  1A5 

So that is ok!!!
But now, when adapting the syntax and using ringbuffer mode (and I hope I 
did the syntax ok):

#include "stdio.h"
#include "libpruio/pruio.h" // include header
#include <unistd.h>

int main(int argc, char **argv)
{
    int i, n;
    pruIo *io = pruio_new(PRUIO_DEF_ACTIVE, 4, 0x98, 0);
    
  pruio_adc_setStep(io, 7, 0, 1, 0, 0);    //Step 1, AIN-0
  pruio_adc_setStep(io, 8, 1, 1, 0, 0);   //Step 2, AIN-1
  pruio_adc_setStep(io, 9, 2, 1, 0, 0);   //Step 3, AIN-2
  pruio_adc_setStep(io, 10, 3, 1, 0, 0);    //Step 4, AIN-3
  pruio_adc_setStep(io, 11, 4, 1, 0, 0);   //Step 5, AIN-4
  pruio_adc_setStep(io, 12, 5, 1, 0, 0);    //Step 6, AIN-5
  pruio_adc_setStep(io, 13, 6, 1, 0, 0);   //Step 7, AIN-6
  pruio_adc_setStep(io, 14, 7, 1, 0, 0);   //Step 8, AIN-7
  
    if (pruio_config(io, 220500, 255<<7 , 45352, 0)){ // upload (default) 
settings, start IO mode
                               printf("config failed (%s)\n", io->Errr);}  
    if (pruio_rb_start(io)) printf("rb_start failed (%s)\n", io->Errr); // 
start measurement   //Starts in rb_mode
    printf("initialized\n");
    usleep(10000);
/* now current ADC samples are available for AIN-0 to AIN-7 in array 
io->Adc->Value[] */
    for(n = 1; n <= 13; n++) { //                       print some lines
    for(i = 0; i < 8; i++) //                                all steps
         printf(" %4X", io->Adc->Value[i + (8 * n)]); //  output one 
channel in hex
    printf("\n"); //                                         next line
    }
/* we're done */
   pruio_destroy(io);        /* destroy driver structure */
   return 0;
}

output:

  8EF   B7  477    F  10F  E3F   47  19F
  72F   A7  357    F  117  E3F   4F  1A3
  60F   97  2DF   13  11B  E3F   4F  1A3
  557   8F  2B7   17  11F  E3F   4F  1A7
  4DF   8F  2A7   17  11F  E3F   4F  1A7
  49F   7F  29F   17  127  E3F   4F  1A7
  477   7F  29F   17  127  E3F   4F  1A7
  45F   7F  29F   17  127  E4F   53  1A7
  44F   7F  29F   17  127  E3F   4F  1A7
  447   7F  29F   17  127  E3F   4F  1A7
  43F   7F  29F   17  127  E3F   53  1A7
  43F   7F  29F   1B  127  E3F   53  1A7
  43F   7F  29F   17  127  E3F   53  1A7

There are definitely some interesting differences in the output. Loose from 
the  difference in resolution some of the inputs (Ain-0, Ain-1, Ain-2, 
Ain-6) cause very different output from the values that come from the 
minimal code ADC example while Ain-3, Ain-4, Ain-5, Ain-7 are more or less 
the same except for the resolution thing. (Pull-down activated in the 
minimal example?). The battery is connected to Ain-5 in both situations 
using a 10kΩ potmeter on that channel, the other channels are floating so 
maybe we should not pay too much attention to the absolute differences but 
we do see that the resolution thing seems connected to rb-mode unless my 
syntax is false.

Looking for a clue...

Best, Hans.

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