[En-Nut-Discussion] Analog Input

Daniel ziu82 at gmx.de
Wed Sep 9 19:16:45 CEST 2009


Hi all,

Sadly I have to bother you again with ADC issues. I am not able to get a 
signal on the ADC inputs. I've uploaded an image of the simple circuit 
I'm using: (http://www.darthziu.de/Bilder/Circuit.jpg).

I bridged Pin 1&2 on the ADC connector as Harald wrote on 2009/09/02.

Code is as follows (as the example at NutWiki):

int main(void)
{
    // UART registrieren
    u_long baud = 115200;
    NutRegisterDevice(&DEV_UART, 0, 0);
    freopen(DEV_DEBUG_NAME, "w", stdout);
    _ioctl(_fileno(stdout), UART_SETSPEED, &baud);

    puts("\nADC example");
 
    ADCInit();
    uint16_t adc_value = 0;
   
    for (;;) {
       
    ADCStartConversion();   
 
        while (ADCRead(&adc_value))
        {
            NutThreadYield();
        }
 
       printf("Value: %u\n", adc_value);
               NutSleep(1000);
    }
   
    return 0;
}

Get always the same values on the ADC (eg. ADC0==255, ADC7==1023), even 
if I play with the poti. With an external voltage meter I get different 
voltages as expected.

Where is my error? I'm getting insane here. Just tried with 2 Ethernuts, 
every ADC Pin and nearly every ADC software configuration.

Thanks in advance
Daniel



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