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/**
* Testing ADC power up and power down, for timing and actual on/off
* Uses TIM6, because DWT_CYCCNT not available on cm0(+) :(
* (And with no DWT, no ITM timestamping either, get a real mcu!)
*/
#include <stdio.h>
#include <stdint.h>
#include <libopencm3/stm32/adc.h>
#include <libopencm3/stm32/rcc.h>
#include <libopencm3/stm32/timer.h>
#include "adc-power.h"
/* Everyone has tim6 right? */
#define TIMER TIM6
#define TIMER_RCC RCC_TIM6
// TODO - stick this in libopencm3?
#define ARRAY_SIZE(a) (sizeof((a)) / sizeof((a)[0]))
void adc_power_init(void)
{
/* Some basic ADC config, that we won't touch again */
rcc_periph_clock_enable(RCC_ADC1);
adc_set_sample_time_on_all_channels(ADC1, ADC_SMPR_SMP_28CYC);
#if 0
// DANGER DANGER! doing this without DMA is dum.
// but... we're busy polling, we should be right... right?
// (dma across platforms is teh suck)
adc_enable_scan_mode(ADC1);
ADC_CR2 |= ADC_CR2_EOCS; // FIXME
#else
adc_disable_scan_mode(ADC1);
#endif
/*
* We're going to setup a timer to run at top speed, so... "fast"
* but we don't actually care about the rate itself. We just
* want to collect how many ticks it takes to enable and disable
* the adc.
*/
rcc_periph_clock_enable(TIMER_RCC);
timer_reset(TIMER);
timer_set_prescaler(TIMER, 0);
timer_enable_counter(TIMER);
}
static uint16_t read_adc_naiive(uint8_t channel)
{
uint8_t channel_array[16];
channel_array[0] = channel;
adc_set_regular_sequence(ADC1, 1, channel_array);
adc_start_conversion_regular(ADC1);
while (!adc_eoc(ADC1));
return adc_read_regular(ADC1);
}
void adc_power_task_up(void) {
TIM_CNT(TIMER) = 0;
adc_power_on(ADC1);
unsigned int td = TIM_CNT(TIMER);
/* just for kicks, let's time some sequences too....
* I mean, we're going to do some conversions right? */
adc_set_single_conversion_mode(ADC1);
#if 0
uint8_t channels[2] = { 0, 1 };
adc_set_regular_sequence(ADC1, ARRAY_SIZE(channels), channels);
TIM_CNT(TIMER) = 0;
adc_start_conversion_regular(ADC1);
while (!adc_eoc(ADC1));
unsigned int v1 = adc_read_regular(ADC1);
while (!adc_eoc(ADC1));
unsigned int v2 = adc_read_regular(ADC1);
unsigned int tconv = TIM_CNT(TIMER);
#else
TIM_CNT(TIMER) = 0;
unsigned int v1 = read_adc_naiive(0);
unsigned int v2 = read_adc_naiive(1);
unsigned int tconv = TIM_CNT(TIMER);
#endif
printf("ton: %u, tconv: %u, v1: %u, v2: %u\n", td, tconv, v1, v2);
}
void adc_power_task_down()
{
TIM_CNT(TIMER) = 0;
adc_power_off(ADC1);
unsigned int td = TIM_CNT(TIMER);
printf("toff in: %u\n", td);
}
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