Author Topic: help using DAC in LPC925  (Read 82101 times)


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help using DAC in LPC925
« on: March 20, 2007, 11:19:35 AM »
I'm trying to use the DAC as well as the AD in the LPC925 at the same time but I'm having some trouble initializing both of them at the same time. I can get AD1 working fine, but i can't get the DAC to work. I tried using Code Architect but it gives me some strange variables that Keil does not know what it is.
This is what code architect gives me:
void adc_init (void)

  // set dac1 pin to input only (disables digital output)
  P2M1 |= 0x01;
  P2M2 &= ~0x01;
  // init dac1 value to zero
  AD0DAT3 = 0x00;
  // enable dac1 output
  ADMODB |= 0x04;
  // enable adc1 (also enables dac1)
  ADCON0 |= 0x04;


First there is no P2 in the LPC925, so I'm guessing it meant to say P0 instead. Also, there is no AD0DAT3, i think it meant to say AD1DAT3. It also calls for ADCON0 but there is no ADCON0 in the LPC925, there is a ADCON1.
So here is my code Init code for the first two A/Ds (ADC10/P0.1 and ADC11/P0.2) and the DAC1/P.04 active at the same time. Can anyone tell me if this is correct.

void ADC_Init(void)
   // configure clock divider
   ADMODB |= 0x40;
   // set adc1 channel pin to input only (disables digital output)
   // channel 0
   P0M1 |= 0x02;
   P0M2 &= ~0x02;
   P0M1 |= 0x04;
   P0M2 &= ~0x04;

   P0M1 |= 0x10;
   P0M2 &= ~0x10;

   // init dac1 value to zero
   AD1DAT3 = 0x00;
   // enable dac1 output
   ADMODB |= 0x04;
   // configure adc1 and enable (also enables dac1)
   ADCON1 |= 0x44;
   // set isr priority to 0
   IP1 &= 0x7F;
   IP1H &= 0x7F;
   // enable adc interrupt
   EAD = 1;

Or at least where i'm making a mistake since it doesn't work. Also, if need it, i'm using the internal RC clock.
Any helps is greatly appreciated.


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Re: help using DAC in LPC925
« Reply #1 on: March 20, 2007, 12:09:10 PM »
repost at, that is where it belongs