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CommandStation-EX/DCCTimerSTM32.cpp
pmantoine 2ff1619ad1 STM32 reinstate 100% duty cycle PWM
2023-10-04 14:54:06 +08:00

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/*
* © 2023 Neil McKechnie
* © 2022-2023 Paul M. Antoine
* © 2021 Mike S
* © 2021, 2023 Harald Barth
* © 2021 Fred Decker
* © 2021 Chris Harlow
* © 2021 David Cutting
* All rights reserved.
*
* This file is part of Asbelos DCC API
*
* This is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* It is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with CommandStation. If not, see <https://www.gnu.org/licenses/>.
*/
// ATTENTION: this file only compiles on a STM32 based boards
// Please refer to DCCTimer.h for general comments about how this class works
// This is to avoid repetition and duplication.
#ifdef ARDUINO_ARCH_STM32
#include "DCCTimer.h"
#ifdef DEBUG_ADC
#include "TrackManager.h"
#endif
#include "DIAG.h"
#if defined(ARDUINO_NUCLEO_F401RE) || defined(ARDUINO_NUCLEO_F411RE)
// Nucleo-64 boards don't have additional serial ports defined by default
HardwareSerial Serial1(PB7, PA15); // Rx=PB7, Tx=PA15 -- CN7 pins 17 and 21 - F411RE
// Serial2 is defined to use USART2 by default, but is in fact used as the diag console
// via the debugger on the Nucleo-64. It is therefore unavailable for other DCC-EX uses like WiFi, DFPlayer, etc.
// Let's define Serial6 as an additional serial port (the only other option for the Nucleo-64s)
HardwareSerial Serial6(PA12, PA11); // Rx=PA12, Tx=PA11 -- CN10 pins 12 and 14 - F411RE
#elif defined(ARDUINO_NUCLEO_F446RE)
// Nucleo-64 boards don't have additional serial ports defined by default
// On the F446RE, Serial1 isn't really useable as it's Rx/Tx pair sit on already used D2/D10 pins
// HardwareSerial Serial1(PA10, PB6); // Rx=PA10 (D2), Tx=PB6 (D10) -- CN10 pins 17 and 9 - F446RE
// Serial2 is defined to use USART2 by default, but is in fact used as the diag console
// via the debugger on the Nucleo-64. It is therefore unavailable for other DCC-EX uses like WiFi, DFPlayer, etc.
// On the F446RE, Serial3 and Serial5 are easy to use:
HardwareSerial Serial3(PC11, PC10); // Rx=PC11, Tx=PC10 -- USART3 - F446RE
HardwareSerial Serial5(PD2, PC12); // Rx=PC7, Tx=PC6 -- UART5 - F446RE
// On the F446RE, Serial4 and Serial6 also use pins we can't readily map while using the Arduino pins
#elif defined(ARDUINO_NUCLEO_F412ZG) || defined(ARDUINO_NUCLEO_F413ZH) || defined(ARDUINO_NUCLEO_F429ZI) || defined(ARDUINO_NUCLEO_F446ZE)
// Nucleo-144 boards don't have Serial1 defined by default
HardwareSerial Serial6(PG9, PG14); // Rx=PG9, Tx=PG14 -- USART6
// Serial3 is defined to use USART3 by default, but is in fact used as the diag console
// via the debugger on the Nucleo-144. It is therefore unavailable for other DCC-EX uses like WiFi, DFPlayer, etc.
#else
#error STM32 board selected is not yet explicitly supported - so Serial1 peripheral is not defined
#endif
///////////////////////////////////////////////////////////////////////////////////////////////
// Experimental code for High Accuracy (HA) DCC Signal mode
// Warning - use of TIM2 and TIM3 can affect the use of analogWrite() function on certain pins,
// which is used by the DC motor types.
///////////////////////////////////////////////////////////////////////////////////////////////
// INTERRUPT_CALLBACK interruptHandler=0;
// // Let's use STM32's timer #2 which supports hardware pulse generation on pin D13.
// // Also, timer #3 will do hardware pulses on pin D12. This gives
// // accurate timing, independent of the latency of interrupt handling.
// // We only need to interrupt on one of these (TIM2), the other will just generate
// // pulses.
// HardwareTimer timer(TIM2);
// HardwareTimer timerAux(TIM3);
// static bool tim2ModeHA = false;
// static bool tim3ModeHA = false;
// // Timer IRQ handler
// void Timer_Handler() {
// interruptHandler();
// }
// void DCCTimer::begin(INTERRUPT_CALLBACK callback) {
// interruptHandler=callback;
// noInterrupts();
// // adc_set_sample_rate(ADC_SAMPLETIME_480CYCLES);
// timer.pause();
// timerAux.pause();
// timer.setPrescaleFactor(1);
// timer.setOverflow(DCC_SIGNAL_TIME, MICROSEC_FORMAT);
// timer.attachInterrupt(Timer_Handler);
// timer.refresh();
// timerAux.setPrescaleFactor(1);
// timerAux.setOverflow(DCC_SIGNAL_TIME, MICROSEC_FORMAT);
// timerAux.refresh();
// timer.resume();
// timerAux.resume();
// interrupts();
// }
// bool DCCTimer::isPWMPin(byte pin) {
// // Timer 2 Channel 1 controls pin D13, and Timer3 Channel 1 controls D12.
// // Enable the appropriate timer channel.
// switch (pin) {
// case 12:
// return true;
// case 13:
// return true;
// default:
// return false;
// }
// }
// void DCCTimer::setPWM(byte pin, bool high) {
// // Set the timer so that, at the next counter overflow, the requested
// // pin state is activated automatically before the interrupt code runs.
// // TIM2 is timer, TIM3 is timerAux.
// switch (pin) {
// case 12:
// if (!tim3ModeHA) {
// timerAux.setMode(1, TIMER_OUTPUT_COMPARE_INACTIVE, D12);
// tim3ModeHA = true;
// }
// if (high)
// TIM3->CCMR1 = (TIM3->CCMR1 & ~TIM_CCMR1_OC1M_Msk) | TIM_CCMR1_OC1M_0;
// else
// TIM3->CCMR1 = (TIM3->CCMR1 & ~TIM_CCMR1_OC1M_Msk) | TIM_CCMR1_OC1M_1;
// break;
// case 13:
// if (!tim2ModeHA) {
// timer.setMode(1, TIMER_OUTPUT_COMPARE_INACTIVE, D13);
// tim2ModeHA = true;
// }
// if (high)
// TIM2->CCMR1 = (TIM2->CCMR1 & ~TIM_CCMR1_OC1M_Msk) | TIM_CCMR1_OC1M_0;
// else
// TIM2->CCMR1 = (TIM2->CCMR1 & ~TIM_CCMR1_OC1M_Msk) | TIM_CCMR1_OC1M_1;
// break;
// }
// }
// void DCCTimer::clearPWM() {
// timer.setMode(1, TIMER_OUTPUT_COMPARE_INACTIVE, NC);
// tim2ModeHA = false;
// timerAux.setMode(1, TIMER_OUTPUT_COMPARE_INACTIVE, NC);
// tim3ModeHA = false;
// }
///////////////////////////////////////////////////////////////////////////////////////////////
INTERRUPT_CALLBACK interruptHandler=0;
// On STM32F4xx models that have them, Timers 6 and 7 have no PWM output capability,
// so are good choices for general timer duties - they are used for tone and servo
// in stm32duino so we shall usurp those as DCC-EX doesn't use tone or servo libs.
// NB: the F401, F410 and F411 do **not** have Timer 6 or 7, so we use Timer 11
#ifndef DCC_EX_TIMER
#if defined(TIM6)
#define DCC_EX_TIMER TIM6
#elif defined(TIM7)
#define DCC_EX_TIMER TIM7
#elif defined(TIM11)
#define DCC_EX_TIMER TIM11
#else
#warning This STM32F4XX variant does not have Timers 6,7 or 11!!
#endif
#endif // ifndef DCC_EX_TIMER
HardwareTimer dcctimer(DCC_EX_TIMER);
void DCCTimer_Handler() __attribute__((interrupt));
// Timer IRQ handler
void DCCTimer_Handler() {
interruptHandler();
}
void DCCTimer::begin(INTERRUPT_CALLBACK callback) {
interruptHandler=callback;
noInterrupts();
dcctimer.pause();
dcctimer.setPrescaleFactor(1);
// timer.setOverflow(CLOCK_CYCLES * 2);
dcctimer.setOverflow(DCC_SIGNAL_TIME, MICROSEC_FORMAT);
// dcctimer.attachInterrupt(Timer11_Handler);
dcctimer.attachInterrupt(DCCTimer_Handler);
dcctimer.setInterruptPriority(0, 0); // Set highest preemptive priority!
dcctimer.refresh();
dcctimer.resume();
interrupts();
}
bool DCCTimer::isPWMPin(byte pin) {
//TODO: STM32 whilst this call to digitalPinHasPWM will reveal which pins can do PWM,
// there's no support yet for High Accuracy, so for now return false
// return digitalPinHasPWM(pin);
(void) pin;
return false;
}
void DCCTimer::setPWM(byte pin, bool high) {
// TODO: High Accuracy mode is not supported as yet, and may never need to be
(void) pin;
(void) high;
}
void DCCTimer::clearPWM() {
return;
}
void DCCTimer::getSimulatedMacAddress(byte mac[6]) {
volatile uint32_t *serno1 = (volatile uint32_t *)0x1FFF7A10;
volatile uint32_t *serno2 = (volatile uint32_t *)0x1FFF7A14;
// volatile uint32_t *serno3 = (volatile uint32_t *)0x1FFF7A18;
volatile uint32_t m1 = *serno1;
volatile uint32_t m2 = *serno2;
mac[0] = m1 >> 8;
mac[1] = m1 >> 0;
mac[2] = m2 >> 24;
mac[3] = m2 >> 16;
mac[4] = m2 >> 8;
mac[5] = m2 >> 0;
}
volatile int DCCTimer::minimum_free_memory=__INT_MAX__;
// Return low memory value...
int DCCTimer::getMinimumFreeMemory() {
noInterrupts(); // Disable interrupts to get volatile value
int retval = freeMemory();
interrupts();
return retval;
}
extern "C" char* sbrk(int incr);
int DCCTimer::freeMemory() {
char top;
return (int)(&top - reinterpret_cast<char *>(sbrk(0)));
}
void DCCTimer::reset() {
__disable_irq();
NVIC_SystemReset();
while(true) {};
}
// TODO: rationalise the size of these... could really use sparse arrays etc.
static HardwareTimer * pin_timer[100] = {0};
static uint32_t channel_frequency[100] = {0};
static uint32_t pin_channel[100] = {0};
// Using the HardwareTimer library API included in stm32duino core to handle PWM duties
// TODO: in order to use the HA code above which Neil kindly wrote, we may have to do something more
// sophisticated about detecting any clash between the timer we'd like to use for PWM and the ones
// currently used for HA so they don't interfere with one another. For now we'll just make PWM
// work well... then work backwards to integrate with HA mode if we can.
void DCCTimer::DCCEXanalogWriteFrequency(uint8_t pin, uint32_t frequency)
{
if (pin_timer[pin] == NULL) {
// Automatically retrieve TIM instance and channel associated to pin
// This is used to be compatible with all STM32 series automatically.
TIM_TypeDef *Instance = (TIM_TypeDef *)pinmap_peripheral(digitalPinToPinName(pin), PinMap_PWM);
if (Instance == NULL) {
// We shouldn't get here (famous last words) as it ought to have been caught by brakeCanPWM()!
DIAG(F("DCCEXanalogWriteFrequency::Pin %d has no PWM function!"), pin);
return;
}
pin_channel[pin] = STM_PIN_CHANNEL(pinmap_function(digitalPinToPinName(pin), PinMap_PWM));
// Instantiate HardwareTimer object. Thanks to 'new' instantiation,
// HardwareTimer is not destructed when setup function is finished.
pin_timer[pin] = new HardwareTimer(Instance);
// Configure and start PWM
// MyTim->setPWM(channel, pin, 5, 10, NULL, NULL); // No callback required, we can simplify the function call
if (pin_timer[pin] != NULL)
{
pin_timer[pin]->setPWM(pin_channel[pin], pin, frequency, 0); // set frequency in Hertz, 0% dutycycle
DIAG(F("DCCEXanalogWriteFrequency::Pin %d on Timer %d, frequency %d"), pin, pin_channel[pin], frequency);
}
else
DIAG(F("DCCEXanalogWriteFrequency::failed to allocate HardwareTimer instance!"));
}
else
{
// Frequency change request
if (frequency != channel_frequency[pin])
{
pinmap_pinout(digitalPinToPinName(pin), PinMap_TIM); // ensure the pin has been configured!
pin_timer[pin]->setOverflow(frequency, HERTZ_FORMAT); // Just change the frequency if it's already running!
DIAG(F("DCCEXanalogWriteFrequency::setting frequency to %d"), frequency);
}
}
channel_frequency[pin] = frequency;
return;
}
void DCCTimer::DCCEXanalogWrite(uint8_t pin, int value) {
// Calculate percentage duty cycle from value given
uint32_t duty_cycle = (value * 100 / 256) + 1;
if (pin_timer[pin] != NULL) {
// if (duty_cycle == 100)
// {
// pin_timer[pin]->pauseChannel(pin_channel[pin]);
// DIAG(F("DCCEXanalogWrite::Pausing timer channel on pin %d"), pin);
// }
// else
// {
pinmap_pinout(digitalPinToPinName(pin), PinMap_TIM); // ensure the pin has been configured!
// pin_timer[pin]->resumeChannel(pin_channel[pin]);
pin_timer[pin]->setCaptureCompare(pin_channel[pin], duty_cycle, PERCENT_COMPARE_FORMAT); // DCC_EX_PWM_FREQ Hertz, duty_cycle% dutycycle
DIAG(F("DCCEXanalogWrite::Pin %d, value %d, duty cycle %d"), pin, value, duty_cycle);
// }
}
else
DIAG(F("DCCEXanalogWrite::Pin %d is not configured for PWM!"), pin);
}
// Now we can handle more ADCs, maybe this works!
#define NUM_ADC_INPUTS NUM_ANALOG_INPUTS
uint32_t ADCee::usedpins = 0; // Max of 32 ADC input channels!
uint8_t ADCee::highestPin = 0; // Highest pin to scan
int * ADCee::analogvals = NULL; // Array of analog values last captured
uint32_t * analogchans = NULL; // Array of channel numbers to be scanned
// bool adc1configured = false;
ADC_TypeDef * * adcchans = NULL; // Array to capture which ADC is each input channel on
int16_t ADCee::ADCmax()
{
return 4095;
}
int ADCee::init(uint8_t pin) {
int value = 0;
PinName stmpin = analogInputToPinName(pin);
if (stmpin == NC) // do not continue if this is not an analog pin at all
return -1024; // some silly value as error
uint32_t stmgpio = STM_PORT(stmpin); // converts to the GPIO port (16-bits per port group on STM32)
uint32_t adcchan = STM_PIN_CHANNEL(pinmap_function(stmpin, PinMap_ADC)); // find ADC input channel
ADC_TypeDef *adc = (ADC_TypeDef *)pinmap_find_peripheral(stmpin, PinMap_ADC); // find which ADC this pin is on ADC1/2/3 etc.
int adcnum = 1;
if (adc == ADC1)
DIAG(F("ADCee::init(): found pin %d on ADC1"), pin);
// Checking for ADC2 and ADC3 being defined helps cater for more variants later
#if defined(ADC2)
else if (adc == ADC2)
{
DIAG(F("ADCee::init(): found pin %d on ADC2"), pin);
adcnum = 2;
}
#endif
#if defined(ADC3)
else if (adc == ADC3)
{
DIAG(F("ADCee::init(): found pin %d on ADC3"), pin);
adcnum = 3;
}
#endif
else DIAG(F("ADCee::init(): found pin %d on unknown ADC!"), pin);
// Port config - find which port we're on and power it up
GPIO_TypeDef *gpioBase;
switch (stmgpio)
{
case 0x00:
RCC->AHB1ENR |= RCC_AHB1ENR_GPIOAEN; //Power up PORTA
gpioBase = GPIOA;
break;
case 0x01:
RCC->AHB1ENR |= RCC_AHB1ENR_GPIOBEN; //Power up PORTB
gpioBase = GPIOB;
break;
case 0x02:
RCC->AHB1ENR |= RCC_AHB1ENR_GPIOCEN; //Power up PORTC
gpioBase = GPIOC;
break;
case 0x03:
RCC->AHB1ENR |= RCC_AHB1ENR_GPIODEN; //Power up PORTD
gpioBase = GPIOD;
break;
case 0x04:
RCC->AHB1ENR |= RCC_AHB1ENR_GPIOEEN; //Power up PORTE
gpioBase = GPIOE;
break;
#if defined(GPIOF)
case 0x05:
RCC->AHB1ENR |= RCC_AHB1ENR_GPIOFEN; //Power up PORTF
gpioBase = GPIOF;
break;
#endif
default:
return -1023; // some silly value as error
}
// Set pin mux mode to analog input, the 32 bit port mode register has 2 bits per pin
gpioBase->MODER |= (0b011 << (STM_PIN(stmpin) << 1)); // Set pin mux to analog mode (binary 11)
// Set the sampling rate for that analog input
// This is F411x specific! Different on for example F334
// STM32F11xC/E Reference manual
// 11.12.4 ADC sample time register 1 (ADC_SMPR1) (channels 10 to 18)
// 11.12.5 ADC sample time register 2 (ADC_SMPR2) (channels 0 to 9)
if (adcchan > 18)
return -1022; // silly value as error
if (adcchan < 10)
adc->SMPR2 |= (0b111 << (adcchan * 3)); // Channel sampling rate 480 cycles
else
adc->SMPR1 |= (0b111 << ((adcchan - 10) * 3)); // Channel sampling rate 480 cycles
// Read the inital ADC value for this analog input
adc->SQR3 = adcchan; // 1st conversion in regular sequence
adc->CR2 |= ADC_CR2_SWSTART; //(1 << 30); // Start 1st conversion SWSTART
while(!(adc->SR & (1 << 1))); // Wait until conversion is complete
value = adc->DR; // Read value from register
uint8_t id = pin - PNUM_ANALOG_BASE;
// if (id > 15) { // today we have not enough bits in the mask to support more
// return -1021;
// }
if (analogvals == NULL) { // allocate analogvals, analogchans and adcchans if this is the first invocation of init
analogvals = (int *)calloc(NUM_ADC_INPUTS+1, sizeof(int));
analogchans = (uint32_t *)calloc(NUM_ADC_INPUTS+1, sizeof(uint32_t));
adcchans = (ADC_TypeDef **)calloc(NUM_ADC_INPUTS+1, sizeof(ADC_TypeDef));
}
analogvals[id] = value; // Store sampled value
analogchans[id] = adcchan; // Keep track of which ADC channel is used for reading this pin
adcchans[id] = adc; // Keep track of which ADC this channel is on
usedpins |= (1 << id); // This pin is now ready
if (id > highestPin) highestPin = id; // Store our highest pin in use
DIAG(F("ADCee::init(): value=%d, ADC%d: channel=%d, id=%d"), value, adcnum, adcchan, id);
return value;
}
/*
* Read function ADCee::read(pin) to get value instead of analogRead(pin)
*/
int ADCee::read(uint8_t pin, bool fromISR) {
uint8_t id = pin - PNUM_ANALOG_BASE;
// Was this pin initialised yet?
if ((usedpins & (1<<id) ) == 0)
return -1023;
// We do not need to check (analogvals == NULL)
// because usedpins would still be 0 in that case
return analogvals[id];
}
/*
* Scan function that is called from interrupt
*/
#pragma GCC push_options
#pragma GCC optimize ("-O3")
void ADCee::scan() {
static uint8_t id = 0; // id and mask are the same thing but it is faster to
static uint16_t mask = 1; // increment and shift instead to calculate mask from id
static bool waiting = false;
static ADC_TypeDef *adc;
adc = adcchans[id];
if (waiting)
{
// look if we have a result
if (!(adc->SR & (1 << 1)))
return; // no result, continue to wait
// found value
analogvals[id] = adc->DR;
// advance at least one track
#ifdef DEBUG_ADC
if (id == 1) TrackManager::track[1]->setBrake(0);
#endif
waiting = false;
id++;
mask = mask << 1;
if (id > highestPin) { // the 1 has been shifted out
id = 0;
mask = 1;
}
}
if (!waiting) {
if (usedpins == 0) // otherwise we would loop forever
return;
// look for a valid track to sample or until we are around
while (true) {
if (mask & usedpins) {
// start new ADC aquire on id
adc = adcchans[id];
adc->SQR3 = analogchans[id]; // 1st conversion in regular sequence
adc->CR2 |= (1 << 30); // Start 1st conversion SWSTART
#ifdef DEBUG_ADC
if (id == 1) TrackManager::track[1]->setBrake(1);
#endif
waiting = true;
return;
}
id++;
mask = mask << 1;
if (id > highestPin) {
id = 0;
mask = 1;
}
}
}
}
#pragma GCC pop_options
void ADCee::begin() {
noInterrupts();
//ADC1 config sequence
RCC->APB2ENR |= RCC_APB2ENR_ADC1EN; // Enable ADC1 clock
// Set ADC prescaler - DIV8 ~ 40ms, DIV6 ~ 30ms, DIV4 ~ 20ms, DIV2 ~ 11ms
ADC->CCR = (0 << 16); // Set prescaler 0=DIV2, 1=DIV4, 2=DIV6, 3=DIV8
ADC1->CR1 &= ~(1 << 8); //SCAN mode disabled (Bit8)
ADC1->CR1 &= ~(3 << 24); //12bit resolution (Bit24,25 0b00)
ADC1->SQR1 = (1 << 20); //Set number of conversions projected (L[3:0] 0b0001) -> 1 conversion
// Disable the DMA controller for ADC1
ADC1->CR2 &= ~ADC_CR2_DMA;
ADC1->CR2 &= ~(1 << 1); //Single conversion
ADC1->CR2 &= ~(1 << 11); //Right alignment of data bits bit12....bit0
ADC1->SQR1 &= ~(0x3FFFFFFF); //Clear whole 1st 30bits in register
ADC1->SQR2 &= ~(0x3FFFFFFF); //Clear whole 1st 30bits in register
ADC1->SQR3 &= ~(0x3FFFFFFF); //Clear whole 1st 30bits in register
ADC1->CR2 |= (1 << 0); // Switch on ADC1
// Wait for ADC1 to become ready (calibration complete)
while (!(ADC1->CR2 & ADC_CR2_ADON)) {
}
#if defined(ADC2)
// Enable the ADC2 clock
RCC->APB2ENR |= RCC_APB2ENR_ADC2EN;
// Initialize ADC2
ADC2->CR1 = 0; // Disable all channels
ADC2->CR2 = 0; // Clear CR2 register
ADC2->CR1 &= ~(1 << 8); //SCAN mode disabled (Bit8)
ADC2->CR1 &= ~(3 << 24); //12bit resolution (Bit24,25 0b00)
ADC2->SQR1 = (1 << 20); //Set number of conversions projected (L[3:0] 0b0001) -> 1 conversion
ADC2->CR2 &= ~ADC_CR2_DMA; // Disable the DMA controller for ADC3
ADC2->CR2 &= ~(1 << 1); //Single conversion
ADC2->CR2 &= ~(1 << 11); //Right alignment of data bits bit12....bit0
ADC2->SQR1 &= ~(0x3FFFFFFF); //Clear whole 1st 30bits in register
ADC2->SQR2 &= ~(0x3FFFFFFF); //Clear whole 1st 30bits in register
ADC2->SQR3 &= ~(0x3FFFFFFF); //Clear whole 1st 30bits in register
// Enable the ADC
ADC2->CR2 |= ADC_CR2_ADON;
// Wait for ADC2 to become ready (calibration complete)
while (!(ADC2->CR2 & ADC_CR2_ADON)) {
}
// Perform ADC3 calibration (optional)
// ADC3->CR2 |= ADC_CR2_CAL;
// while (ADC3->CR2 & ADC_CR2_CAL) {
// }
#endif
#if defined(ADC3)
// Enable the ADC3 clock
RCC->APB2ENR |= RCC_APB2ENR_ADC3EN;
// Initialize ADC3
ADC3->CR1 = 0; // Disable all channels
ADC3->CR2 = 0; // Clear CR2 register
ADC3->CR1 &= ~(1 << 8); //SCAN mode disabled (Bit8)
ADC3->CR1 &= ~(3 << 24); //12bit resolution (Bit24,25 0b00)
ADC3->SQR1 = (1 << 20); //Set number of conversions projected (L[3:0] 0b0001) -> 1 conversion
ADC3->CR2 &= ~ADC_CR2_DMA; // Disable the DMA controller for ADC3
ADC3->CR2 &= ~(1 << 1); //Single conversion
ADC3->CR2 &= ~(1 << 11); //Right alignment of data bits bit12....bit0
ADC3->SQR1 &= ~(0x3FFFFFFF); //Clear whole 1st 30bits in register
ADC3->SQR2 &= ~(0x3FFFFFFF); //Clear whole 1st 30bits in register
ADC3->SQR3 &= ~(0x3FFFFFFF); //Clear whole 1st 30bits in register
// Enable the ADC
ADC3->CR2 |= ADC_CR2_ADON;
// Wait for ADC3 to become ready (calibration complete)
while (!(ADC3->CR2 & ADC_CR2_ADON)) {
}
// Perform ADC3 calibration (optional)
// ADC3->CR2 |= ADC_CR2_CAL;
// while (ADC3->CR2 & ADC_CR2_CAL) {
// }
#endif
interrupts();
}
#endif
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