111 lines
3.1 KiB
C
111 lines
3.1 KiB
C
// ADC functions on STM32F1
|
|
//
|
|
// Copyright (C) 2018 Grigori Goronzy <greg@kinoho.net>
|
|
//
|
|
// This file may be distributed under the terms of the GNU GPLv3 license.
|
|
|
|
#include <stdbool.h> // bool
|
|
#include "board/io.h" // readb
|
|
#include "command.h" // shutdown
|
|
#include "compiler.h" // ARRAY_SIZE
|
|
#include "gpio.h" // gpio_adc_setup
|
|
#include "internal.h" // GPIO
|
|
#include "stm32f1xx_ll_adc.h" // LL_ADC_REG_ReadConversionData12
|
|
#include "stm32f1xx_ll_gpio.h" // LL_GPIO_SetPinMode
|
|
#include "sched.h" // sched_shutdown
|
|
|
|
DECL_CONSTANT(ADC_MAX, 4095);
|
|
|
|
#define ADC_DELAY (240 * 8)
|
|
|
|
static bool adc_busy;
|
|
static uint32_t adc_current_channel;
|
|
|
|
static const uint8_t adc_pins[] = {
|
|
GPIO('A', 0), GPIO('A', 1), GPIO('A', 2), GPIO('A', 3),
|
|
GPIO('A', 4), GPIO('A', 5), GPIO('A', 6), GPIO('A', 7),
|
|
GPIO('B', 0), GPIO('B', 1), GPIO('C', 0), GPIO('C', 1),
|
|
GPIO('C', 2), GPIO('C', 3), GPIO('C', 4), GPIO('C', 5)
|
|
};
|
|
|
|
static const uint32_t adc_channels[] = {
|
|
LL_ADC_CHANNEL_0,
|
|
LL_ADC_CHANNEL_1,
|
|
LL_ADC_CHANNEL_2,
|
|
LL_ADC_CHANNEL_3,
|
|
LL_ADC_CHANNEL_4,
|
|
LL_ADC_CHANNEL_5,
|
|
LL_ADC_CHANNEL_6,
|
|
LL_ADC_CHANNEL_7,
|
|
LL_ADC_CHANNEL_8,
|
|
LL_ADC_CHANNEL_9,
|
|
LL_ADC_CHANNEL_10,
|
|
LL_ADC_CHANNEL_11,
|
|
LL_ADC_CHANNEL_12,
|
|
LL_ADC_CHANNEL_13,
|
|
LL_ADC_CHANNEL_14,
|
|
LL_ADC_CHANNEL_15,
|
|
};
|
|
|
|
struct gpio_adc
|
|
gpio_adc_setup(uint8_t pin)
|
|
{
|
|
// Find pin in adc_pins table
|
|
int chan;
|
|
for (chan=0; ; chan++) {
|
|
if (chan >= ARRAY_SIZE(adc_pins))
|
|
shutdown("Not a valid ADC pin");
|
|
if (adc_pins[chan] == pin)
|
|
break;
|
|
}
|
|
|
|
GPIO_TypeDef *regs = digital_regs[GPIO2PORT(pin)];
|
|
uint32_t bit = digital_pins[pin % 16];
|
|
LL_GPIO_SetPinMode(regs, bit, LL_GPIO_MODE_ANALOG);
|
|
|
|
return (struct gpio_adc){ .bit = adc_channels[chan] };
|
|
}
|
|
|
|
// Try to sample a value. Returns zero if sample ready, otherwise
|
|
// returns the number of clock ticks the caller should wait before
|
|
// retrying this function.
|
|
uint32_t
|
|
gpio_adc_sample(struct gpio_adc g)
|
|
{
|
|
/* ADC not busy, start conversion */
|
|
if (!readb(&adc_busy)) {
|
|
LL_ADC_REG_SetSequencerRanks(ADC1, LL_ADC_REG_RANK_1, g.bit);
|
|
LL_ADC_SetChannelSamplingTime(ADC1, g.bit
|
|
, LL_ADC_SAMPLINGTIME_239CYCLES_5);
|
|
LL_ADC_REG_StartConversionSWStart(ADC1);
|
|
adc_busy = true;
|
|
adc_current_channel = g.bit;
|
|
return ADC_DELAY;
|
|
/* ADC finished conversion for this channel */
|
|
} else if (LL_ADC_IsActiveFlag_EOS(ADC1) &&
|
|
readl(&adc_current_channel) == g.bit) {
|
|
LL_ADC_ClearFlag_EOS(ADC1);
|
|
adc_busy = false;
|
|
return 0;
|
|
}
|
|
/* Wants to sample another channel, or not finished yet */
|
|
return ADC_DELAY;
|
|
}
|
|
|
|
// Read a value; use only after gpio_adc_sample() returns zero
|
|
uint16_t
|
|
gpio_adc_read(struct gpio_adc g)
|
|
{
|
|
return LL_ADC_REG_ReadConversionData12(ADC1);
|
|
}
|
|
|
|
// Cancel a sample that may have been started with gpio_adc_sample()
|
|
void
|
|
gpio_adc_cancel_sample(struct gpio_adc g)
|
|
{
|
|
if (readb(&adc_busy) && readl(&adc_current_channel) == g.bit) {
|
|
adc_busy = false;
|
|
LL_ADC_ClearFlag_EOS(ADC1);
|
|
}
|
|
}
|