/**
* \brief Initialize ADC.
*/
static void demo_config_adc( void )
{
/* Enable peripheral clock. */
pmc_enable_periph_clk(ID_ADC);
/* Initialize ADC. */
/*
* Formula: ADCClock = MCK / ( (PRESCAL+1) * 2 )
* For example, MCK = 64MHZ, PRESCAL = 4, then:
* ADCClock = 64 / ((4+1) * 2) = 6.4MHz;
*/
/* Formula:
* Startup Time = startup value / ADCClock
* Startup time = 64 / 6.4MHz = 10 us
*/
adc_init(ADC, sysclk_get_cpu_hz(), 6400000, ADC_STARTUP_TIME_4);
/* Formula:
* Transfer Time = (TRANSFER * 2 + 3) / ADCClock
* Tracking Time = (TRACKTIM + 1) / ADCClock
* Settling Time = settling value / ADCClock
*
* Transfer Time = (1 * 2 + 3) / 6.4MHz = 781 ns
* Tracking Time = (1 + 1) / 6.4MHz = 312 ns
* Settling Time = 3 / 6.4MHz = 469 ns
*/
adc_configure_timing(ADC, TRACKING_TIME, ADC_SETTLING_TIME_3, TRANSFER_PERIOD);
adc_check(ADC, sysclk_get_cpu_hz());
/* Hardware trigger TIOA0. */
adc_configure_trigger(ADC, ADC_TRIG_TIO_CH_1, 0);
/* Enable channels for x,y and z. */
adc_enable_channel(ADC, ADC_CHANNEL_POTENTIOMETER);
/* Configure TC. */
demo_configure_tc0();
}
/**
* \brief Initialize ADC.
*/
static void demo_config_adc( void )
{
/* Enable peripheral clock. */
pmc_enable_periph_clk(ID_ADC);
/* Initialize ADC. */
/* startup = 10: 640 periods of ADCClock
* for prescale = 4
* prescale: ADCClock = MCK / ( (PRESCAL+1) * 2 ) => 64MHz /
* ((4+1)*2) = 6.4MHz
* ADC clock = 6.4 MHz
*/
adc_init(ADC, sysclk_get_cpu_hz(), 6400000, 10);
adc_configure_timing(ADC, 0, ADC_SETTLING_TIME_3, 1);
adc_check(ADC, sysclk_get_cpu_hz());
/* Hardware trigger TIOA0. */
adc_configure_trigger(ADC, ADC_TRIG_TIO_CH_1, 0);
/* Enable channels for x,y and z. */
adc_enable_channel(ADC, ADC_CHANNEL_POTENTIOMETER);
/* Configure TC. */
demo_configure_tc0();
}
