How to use DAC1 Channel 1 and Channel 2?

[Raphael]

Hello,

I want to use both channels of DAC1 without dual mode.
DAC1 Channel 1 works fine, but I can't get the Channel 2 working in the same way.

I took the code from the example \testhal\STM32\STM32F4xx\DAC and copied it for Channel 2 with GPTD7 to trigger it.

Greetings
Raphael

[Giovanni]

Hi,

Unfortunately the current driver does not support independent use of channel 2. It would require significant changes.

Giovanni

[neums]

Hi,
i asked the same in the thread http://forum.chibios.org/phpbb/viewtopic.php?f=16&t=2714. I thought that it is not possible with the current driver but i missunderstood the code in dac_lld.c. Sorry Giovanni.
I did it this way where both DAC Channels are triggered by GPT6:

Code: Select all

#define DAC_BUFFER_SIZE 1

/*
 * DAC buffer.
 */
dacsample_t dac_buffer[DAC_BUFFER_SIZE] = {
  4095
};

/*
 * DAC2 buffer
 */
dacsample_t dac2_buffer[DAC_BUFFER_SIZE] = {
  4095
};

/*
 * GPT6 configuration.
 */
static const GPTConfig gpt6cfg1 = {
  frequency:    10000U,
  callback:     NULL,
  cr2:          TIM_CR2_MMS_1,  /* MMS = 010 = TRGO on Update Event.        */
  dier:         0U
};
/*
 * DAC 1 configuration
 */
static const DACConfig dac1cfg1 = {
  init:         0,
  datamode:     DAC_DHRM_12BIT_RIGHT
};

static const DACConversionGroup dacgrpcfg1 = {
  num_channels: 1U,
  end_cb:       NULL,       //end_cb1
  error_cb:     NULL,       //error_cb1
  trigger:      DAC_TRG(0)
};

/*
 * DAC 2 configuration
 */
static const DACConfig dac1cfg2 = {
   init:        0,
   datamode:    DAC_DHRM_12BIT_RIGHT
};

static const DACConversionGroup dacgrpcfg2 = {
  num_channels: 1U,
  end_cb:       NULL,
  error_cb:     NULL,
  trigger:      DAC_TRG(0)
};

void DACInit(void)
{
    palSetPadMode(GPIOA, 4, PAL_MODE_INPUT_ANALOG);
    palSetPadMode(GPIOA, 5, PAL_MODE_INPUT_ANALOG);
    dacStart(&DACD1, &dac1cfg1);
    dacStart(&DACD2, &dac1cfg2);
    gptStart(&GPTD6, &gpt6cfg1);
    dacStartConversion(&DACD1, &dacgrpcfg1, dac_buffer, DAC_BUFFER_SIZE);
    dacStartConversion(&DACD2, &dacgrpcfg2, dac2_buffer, DAC_BUFFER_SIZE);
    gptStartContinuous(&GPTD6, 2U);
}

But take care about the bug report http://sourceforge.net/p/chibios/bugs/624/. Without this fix the DAC1Ch2 fails.

[Giovanni]

Hi,

It has already been fixed on the repository (trunk).

Giovanni