I have been using STM32 IDE which incorporates the CUBE MX.
Using the HAL code I am able to read on three pins using a separate ADC for each
pin.
I have started all the ADC's at the same time and then I poll for completion.
I am I correct in thinking these ADC reads should be practically simultaneous (i.e.
they all read in at a very similar time)?
Code fragment below.
Using a NUCLEO-STM32 F446RE btw.
MX_ADC1_Init();
MX_ADC2_Init();
MX_ADC3_Init();
MX_USART1_UART_Init();
/* USER CODE BEGIN 2 */
/* USER CODE END 2 */
/* Infinite loop */
/* USER CODE BEGIN WHILE */
while (1)
{
static int flip,sysclk=0,old_sysclk=0,adc1,adc2,adc3;//adc3_0,adc3_1,adc3_2, adc_pstat0,
int adc_pstat1, adc_pstat2, adc_pstat3;
flip ^= 1;
HAL_GPIO_WritePin(GPIOC,GPIO_PIN_0/*|GPIO_PIN_2|GPIO_PIN_6*/, flip);
HAL_ADC_Start(&hadc3);
HAL_ADC_Start(&hadc2);
HAL_ADC_Start(&hadc1);
adc_pstat1 = HAL_ADC_PollForConversion(&hadc1, 10);
adc_pstat3 = HAL_ADC_PollForConversion(&hadc3, 10); // should already be done!
adc_pstat2 = HAL_ADC_PollForConversion(&hadc2, 10); // should already be done!
adc3 = HAL_ADC_GetValue(&hadc3);
adc2 = HAL_ADC_GetValue(&hadc2);
adc1 = HAL_ADC_GetValue(&hadc1);
if (adc_pstat2 ||adc_pstat3)
asm("\t nop");
/* USER CODE END WHILE */
/* USER CODE BEGIN 3 */
sysclk = HAL_GetTick();
if ( (sysclk - 1000) > old_sysclk ){
//printf("nucleo F446 0x%X adc3_0 0x%X adc3_1 0x%X adc3_2 0x%X\n",sysclk,adc3_0,adc3_1,adc3_2);
printf("|->nucleo F446 sysclk=0x%X adc1=0x%X adc2=0x%X adc3=0x%X\n",sysclk,adc1,adc2,adc3);
old_sysclk = sysclk;
}
}
/* USER CODE END 3 */
}
Your code does not read it simultaneously as you do not start the ADCs at the sime moment.
You need to use the same external trigger for all of them or use ADCs in the double or tripple mode.
I found a way to do this easily. I set up a timer and used to to update a trigger event. The ADC's then triggered off this event (TIM8_TRGO).
Using this trigger I can get two or three ADCs to read simultaneously.
The Dual Simultaneous mode seems to support ADCs reading at the same time
I am using a Kinetis KEA64 microcontroller from NXP.
The actual frequency of clock is 20 MHz, and a timer interrupt is generated at every 2.5ms. I have an interrupt handler that toggles an LED when this timer interrupt is generated. LED is toggling on this timer interrupt but i dont know exactly the frequency of LED. Does my LED toggles at 5kHz? Is it correct?
void interrupt_application_timer_FTM0()
{
SIM_SCGC |= SIM_SCGC_FTM0_MASK; /* Enable Clock for FTM0 */
FTM0_SC |= FTM_SC_PS(7); /* Select Preescaler in this case 128. 20 Mhz /128 =156.25 Khz. */
/* Counter increase by one every 6.4 us */
/* Enable Channle 0*/
FTM0_C0SC |= FTM_CnSC_CHIE_MASK; /* Enable channel 0 interrupt */
FTM0_C0SC |= FTM_CnSC_MSA_MASK; /* Channel as Output compare mode */
/*Select interrupt frequency*/
FTM0_C0V = FTM_CnV_VAL(391) ; /* Interrupt every 2.5ms */
FTM0_SC |= FTM_SC_CLKS(1); /*FTM0 use system clock*/
/* Set the ICPR and ISER registers accordingly */
NVIC_ICPR |= 1 << ((INT_FTM0-16)%32);
NVIC_ISER |= 1 << ((INT_FTM0-16)%32);
}
Here is my interrupt handler
void FTM0_IRQHandler()
{
if (1==((FTM0_C0SC & FTM_CnSC_CHF_MASK)>>FTM_CnSC_CHF_SHIFT) ) /* If the CHF of the channel is equal to 0 */
{
(void)FTM0_C0SC; /* Read to clear flag */
FTM0_C0SC ^= FTM_CnSC_CHF_MASK; /* Clear flag */
FTM0_C0V = FTM0_C0V + 391 ; /* Refresh interrupt period */
if (LED_counter>=50){
/* Toggle LED */
/* Reset counter */
LED0_TOGGLE;
LED_counter = 0;
}
LED_counter++;
}
}
Use scope for frequency measuring
In the MCU, you can enable bus clock to one pin (Busclockout), enable that and check the bus clock so that you can confirm your calculations
Then use scope at LED to confirm your frequency
I'm trying to get the external interrupt running on a
Nucleo-F030R8
and hit a wall.
Everything is configured and runs just fine in step mode but when I'm connecting my board to another testboard with a simple jumper wire and run the same code, an External Interrupt is triggered even when that testboard (a second
Nucleo-F302R8,
which should only produce a single signal peak that I want to measure with the first) is not turned on.
I'm using a mix of the HAL Library from STM and a bit code of my own.
Has somebody eventually encountered a similar problem?
I'm using the System Workbench for STM32.
Part of the ISR, Interrupthandler is cut
void EXTI0_1_IRQHandler(void)
{
/* USER CODE BEGIN EXTI0_1_IRQn 0 */
if ((EXTI->IMR & EXTI_IMR_MR0) && (EXTI->PR & EXTI_PR_PR0))
{
int_flag_pin.copen = 1;
}
if ((EXTI->IMR & EXTI_IMR_MR1) && (EXTI->PR & EXTI_PR_PR1))
{
int_flag_pin.ma1 = 1;
}
/* USER CODE END EXTI0_1_IRQn 0 */
HAL_GPIO_EXTI_IRQHandler(GPIO_PIN_0);
HAL_GPIO_EXTI_IRQHandler(GPIO_PIN_1);
/* USER CODE BEGIN EXTI0_1_IRQn 1 */
/* USER CODE END EXTI0_1_IRQn 1 */
}
Between setting the Pin low and change rising, the Interrupt triggers.
TEST_GPIO_Port->BSRR = (uint32_t) TEST_Pin;
//HAL_GPIO_WritePin(TEST_GPIO_Port, TEST_Pin, GPIO_PIN_RESET);
TEST_GPIO_Port->BRR = (uint32_t) TEST_Pin;
change_rising(0);
Update:
Could it be that resetting the Pin through BSRR or BRR generates an interrupt?
I'm checking my code step-by-step and everytime the pin is getting resetted the interrupt is generated.
if TEST_Pin is GPIO_PIN_0 or GPIO_PIN_1 pin, you will receive irq legally. EXTI0_1_IRQHandler catches irq from any port but from #0 or #1 pin.
How I could have 2 interrupts with one handler by this code below:
SYSCFG->EXTICR[0] |= SYSCFG_EXTICR1_EXTI0_PB | SYSCFG_EXTICR1_EXTI1_PC;
EXTI->IMR = EXTI_IMR_MR0 | EXTI_IMR_MR1;
EXTI->RTSR = EXTI_RTSR_TR0| EXTI_RTSR_TR1;
/* Configure NVIC for External Interrupt */
/* (6) Enable Interrupt on EXTI0_1 */
/* (7) Set priority for EXTI0_1 */
NVIC_EnableIRQ(EXTI0_1_IRQn); /* (6) */
NVIC_SetPriority(EXTI0_1_IRQn,0); /* (7) */
This is the code that the handler excecute:
void EXTI0_1_IRQHandler(void)
{
if ((EXTI->PR & EXTI_PR_PR1) == EXTI_PR_PR1) /* Check line 1 has triggered the IT */
{
EXTI->PR = EXTI_PR_PR1; /* Clear the pending bit */
GPIOC->ODR |= 1<<0;
}
if ((EXTI->PR & EXTI_PR_PR0) == EXTI_PR_PR0) /* Check line 0 has triggered the IT */
{
EXTI->PR = EXTI_PR_PR0; /* Clear the pending bit */
GPIOC->ODR &= ~(1<<0);
}
}
The code works fine when I click on the button that is connected to PC1, the LED turns on and when I click on the button that is connected to PB0 the LED turns off.
In my if structures I check which line is active but I also want the LED only turns on by clicking on PC1 and not with a click on another pin on line 1, the same for line 0 but I don't know how I can change the conditions for the if structures.
The micro-controller is a STM32F091.
First: you can't connect more than one pin (A..Fx) per EXTIx line (see RM0091 page 177). So EXTI line 0 IRQ is strictly correspond to one pin: C0 in your code.
Second: don't use IRQs for serve buttons. You must implement bounce filter and best idea for this is check button's pin state by timer. Human reaction is about 200ms, really pushed button will produce pulse with duration 100-200ms. So you need timer with 12-24ms and two bytes in RAM for each button... See code example bellow:
uint8_t btn_state = (uint8_t)0x0, btn_mask = (uint8_t)0x1;
void some_tim_irq_handler(void)
{
if (GPIOC->IDR & (uint16_t)0x1) { // PC0 up
btn_state |= btn_mask;
} else { // PC0 down
btn_state &= (uint8_t)~btn_mask;
}
btn_mask <<= (uint8_t)0x1; // mask cycle
if (btn_state == (uint8_t)0x0) {
// One state
return;
}
if (btn_state == (uint8_t)0xFF) {
// Second state
}
}
I'm developing a C application using avr-libc on an AVR ATmega328P microcontroller. Since I don't have an ICE debugger for it, I followed these instructions and this tutorial for making the stdio.h functions such as printf able to use the hardware UART as stdout.
That works, and I can see the output on a PC terminal connected to my target board, but the strange thing is: When I have only one printf on main, but before the main loop something is causing the processor to reset, while if I have a printf only inside the main loop or before the main loop AND inside the loop it works fine. Something like this:
#include <stdio.h>
/* stream definitions for UART input/output */
FILE uart_output = FDEV_SETUP_STREAM(uart_drv_send_byte, NULL, _FDEV_SETUP_WRITE);
FILE uart_input = FDEV_SETUP_STREAM(NULL, uart_drv_read_byte, _FDEV_SETUP_READ);
int main() {
/* Definition of stdout and stdin */
stdout = &uart_output;
stdin = &uart_input;
/* Configures Timer1 for generating a compare interrupt each 1ms (1kHz) */
timer_init()
/* UART initialization */
uart_drv_start(UBRRH_VALUE, UBRRL_VALUE, USE_2X, &PORTB, 2);
/* Sets the sleep mode to idle */
set_sleep_mode(SLEEP_MODE_IDLE);
printf("START ");
/* main loop */
while(1) {
printf("LOOP ");
/* Sleeps so the main loop iterates only on interrupts (avoids busy loop) */
sleep_mode();
}
}
The code above produces the following output:
START LOOP LOOP LOOP LOOP LOOP LOOP ... LOOP
which is expected. If we comment the printf("START ") line it produces this:
LOOP LOOP LOOP LOOP LOOP LOOP LOOP ... LOOP
which is also fine. The problem is, if I don't have any printf inside the while loop, it goes like this:
START START START START START START ... START
That clearly shows the processor is being restarted, since the expected output would be just one START and nothing else while the infinite loop goes on being awaken only on the 1 kHz timer interrupts. Why is this happening? I should stress there's no watchdog timer configured (if there was, the cases where only LOOP is printed would be interrupted by a new START also).
Monitoring execution using GPIO pins
To try to get some insight into the situation, I turned GPIO pins ON and OFF around the problematic print("START ") and sleep_mode in the main loop:
int main() {
/* Irrelevant parts suppressed... */
GPIO1_ON;
printf("START ");
GPIO1_OFF;
/* Main loop */
while(1) {
/* Sleeps so the main loop iterates only on interrupts (avoids busy loop) */
GPIO2_ON;
sleep_mode();
GPIO2_OFF;
}
}
It turned out that GPIO1 stays ON for 132 µs (printf("START ") call time) and then OFF for 6.6 ms - roughly the time to transmit the six characters at 9600 bit/s - and GPIO2 toggles 12 times (six times two interrupts: the UART-ready-to-transmit interrupt and the UART-empty-data-register interrupt), showing sleep active for another 1.4 ms before GPIO1 goes ON again indicating a new printf("START ") - hence after reset. I'll probably have to check out the UART code, but I'm pretty sure the non-interrupt UART version also shows the same problem, and that doesn't explain either why having a printf inside the main loop works OK, without a reset happening (I would expect the reset would happen in any case should the UART code be faulty).
(SOLVED!): For completeness, The UART init and TX code is below**
This was my first attempt in writing an interrupt driven UART driver for the AVR, but one that could be used either on a RS-232 or a RS-485, which requires activating a TX_ENABLE pin while transmitting data. It turned out that, since I had to make the code useable either on ATmega328P or ATmega644, the interrupt vectors have different names, so I used a #define TX_VECTOR to assume the right name according to the processor used. In the process of making and testing the driver the choosing of "TX_VECTOR" for the UDRE data empty interrupt ended up masking the fact I hadn't defined the USART0_TX_vect yet (this was work in progress, I might not even need both anyway...)
Right now I just defined an empty interrupt service routine (ISR) for USART0_TX_vect and the thing doesn't reset anymore, showing #PeterGibson nailed it right on. Thanks a lot!
// Interrupt vectors for Atmega328P
#if defined(__AVR_ATmega328P__)
#define RX_VECTOR USART_RX_vect
#define TX_VECTOR USART_UDRE_vect
// Interrupt vectors for Atmega644
#elif defined(__AVR_ATmega644P__)
#define RX_VECTOR USART0_RX_vect
#define TX_VECTOR USART0_UDRE_vect
#endif
ISR(TX_VECTOR)
{
uint8_t byte;
if (!ringbuffer_read_byte(&txrb, &byte)) {
/* If RS-485 is enabled, sets TX_ENABLE high */
if (TX_ENABLE_PORT)
*TX_ENABLE_PORT |= _BV(TX_ENABLE_PIN);
UDR0 = byte;
}
else {
/* No more chars to be read from ringbuffer, disables empty
* data register interrupt */
UCSR0B &= ~_BV(UDRIE0);
}
/* If RS-485 mode is on and the interrupt was called with TXC0 set it
* means transmission is over. TX_ENABLED should be cleared. */
if ((TX_ENABLE_PORT) && (UCSR0A & _BV(TXC0) & _BV(UDR0))) {
*TX_ENABLE_PORT &= ~_BV(TX_ENABLE_PIN);
UCSR0B &= ~_BV(UDRIE0);
}
}
void uart_drv_start(uint8_t ubrrh, uint8_t ubrrl, uint8_t use2x,
volatile uint8_t* rs485_tx_enable_io_port,
uint8_t rs485_tx_enable_io_pin)
{
/* Initializes TX and RX ring buffers */
ringbuffer_init(&txrb, &tx_buffer[0], UART_TX_BUFSIZE);
ringbuffer_init(&rxrb, &rx_buffer[0], UART_RX_BUFSIZE);
/* Disables UART */
UCSR0B = 0x00;
/* Initializes baud rate */
UBRR0H = ubrrh;
UBRR0L = ubrrl;
if (use2x)
UCSR0A |= _BV(U2X0);
else
UCSR0A &= ~_BV(U2X0);
/* Configures async 8N1 operation */
UCSR0C = _BV(UCSZ00) | _BV(UCSZ01);
/* If a port was specified for a pin to be used as a RS-485 driver TX_ENABLE,
* configures the pin as output and enables the TX data register empty
* interrupt so it gets disabled in the end of transmission */
if (rs485_tx_enable_io_port) {
TX_ENABLE_PORT = rs485_tx_enable_io_port;
TX_ENABLE_PIN = rs485_tx_enable_io_pin;
/* Configures the RS-485 driver as an output (on the datasheet the data
* direction register is always on the byte preceding the I/O port addr) */
*(TX_ENABLE_PORT-1) |= _BV(TX_ENABLE_PIN);
/* Clears TX_ENABLE pin (active high) */
*TX_ENABLE_PORT &= ~_BV(TX_ENABLE_PIN);
/* Enables end of transmission interrupt */
UCSR0B = _BV(TXCIE0);
}
/* Enables receptor, transmitter and RX complete interrupts */
UCSR0B |= _BV(RXEN0) | _BV(TXEN0) | _BV(RXCIE0);
}
FIXED UART CODE (NOW WORKING 100%!)
In order to help anyone interested or developing a similar interrupt driven UART driver for the AVR ATmega, here it goes the code with the problems above fixed and tested. Thanks to everyone who helped me spot the problem with the missing ISR!
// Interrupt vectors for Atmega328P
#if defined(__AVR_ATmega328P__)
#define RX_BYTE_AVAILABLE USART_RX_vect
#define TX_FRAME_ENDED USART_TX_vect
#define TX_DATA_REGISTER_EMPTY USART_UDRE_vect
// Interrupt vectors for Atmega644
#elif defined(__AVR_ATmega644P__)
#define RX_BYTE_AVAILABLE USART0_RX_vect
#define TX_FRAME_ENDED USART0_TX_vect
#define TX_DATA_REGISTER_EMPTY USART0_UDRE_vect
#endif
/* I/O port containing the pin to be used as TX_ENABLE for the RS-485 driver */
static volatile uint8_t* TX_ENABLE_PORT = NULL;
/** Pin from the I/O port to be used as TX_ENABLE for the RS-485 driver */
static volatile uint8_t TX_ENABLE_PIN = 0;
ISR(RX_BYTE_AVAILABLE)
{
// Read the status and RX registers.
uint8_t status = UCSR0A;
// Framing error - treat as EOF.
if (status & _BV(FE0)) {
/* TODO: increment statistics */
}
// Overrun or parity error.
if (status & (_BV(DOR0) | _BV(UPE0))) {
/* TODO: increment statistics */
}
ringbuffer_write_byte(&rxrb, UDR0);
}
ISR(TX_FRAME_ENDED)
{
/* The end of frame interrupt will be enabled only when in RS-485 mode, so
* there is no need to test, just turn off the TX_ENABLE pin */
*TX_ENABLE_PORT &= ~_BV(TX_ENABLE_PIN);
}
ISR(TX_DATA_REGISTER_EMPTY)
{
uint8_t byte;
if (!ringbuffer_read_byte(&txrb, &byte)) {
/* If RS-485 is enabled, sets TX_ENABLE high */
if (TX_ENABLE_PORT)
*TX_ENABLE_PORT |= _BV(TX_ENABLE_PIN);
UDR0 = byte;
}
else {
/* No more chars to be read from ringbuffer, disables empty
* data register interrupt */
UCSR0B &= ~_BV(UDRIE0);
}
}
void uart_drv_start(uint8_t ubrrh, uint8_t ubrrl, uint8_t use2x,
volatile uint8_t* rs485_tx_enable_io_port,
uint8_t rs485_tx_enable_io_pin)
{
/* Initializes TX and RX ring buffers */
ringbuffer_init(&txrb, &tx_buffer[0], UART_TX_BUFSIZE);
ringbuffer_init(&rxrb, &rx_buffer[0], UART_RX_BUFSIZE);
cli();
/* Disables UART */
UCSR0B = 0x00;
/* Initializes baud rate */
UBRR0H = ubrrh;
UBRR0L = ubrrl;
if (use2x)
UCSR0A |= _BV(U2X0);
else
UCSR0A &= ~_BV(U2X0);
/* Configures async 8N1 operation */
UCSR0C = _BV(UCSZ00) | _BV(UCSZ01);
/* If a port was specified for a pin to be used as a RS-485 driver TX_ENABLE,
* configures the pin as output and enables the TX data register empty
* interrupt so it gets disabled in the end of transmission */
if (rs485_tx_enable_io_port) {
TX_ENABLE_PORT = rs485_tx_enable_io_port;
TX_ENABLE_PIN = rs485_tx_enable_io_pin;
/* Configures the RS-485 driver as an output (on the datasheet the data
* direction register is always on the byte preceding the I/O port addr) */
*(TX_ENABLE_PORT-1) |= _BV(TX_ENABLE_PIN);
/* Clears TX_ENABLE pin (active high) */
*TX_ENABLE_PORT &= ~_BV(TX_ENABLE_PIN);
/* Enables end of transmission interrupt */
UCSR0B = _BV(TXCIE0);
}
/* Enables receptor, transmitter and RX complete interrupts */
UCSR0B |= _BV(RXEN0) | _BV(TXEN0) | _BV(RXCIE0);
sei();
}
void uart_drv_send_byte(uint8_t byte, FILE *stream)
{
if (byte == '\n') {
uart_drv_send_byte('\r', stream);
}
uint8_t sreg = SREG;
cli();
/* Write byte to the ring buffer, blocking while it is full */
while(ringbuffer_write_byte(&txrb, byte)) {
/* Enable interrupts to allow emptying a full buffer */
SREG = sreg;
_NOP();
sreg = SREG;
cli();
}
/* Enables empty data register interrupt */
UCSR0B |= _BV(UDRIE0);
SREG = sreg;
}
uint8_t uart_drv_read_byte(FILE *stream)
{
uint8_t byte;
uint8_t sreg = SREG;
cli();
ringbuffer_read_byte(&rxrb, &byte);
SREG = sreg;
return byte;
}
You've possibly enabled the UDRE (Uart Data Register Empty) interrupt and not set a vector for it, so when the interrupt triggers the processor resets (according to the defaults). When printf is called continuously in the main loop, this interrupt is never triggered.
From the docs
Catch-all interrupt vector
If an unexpected interrupt occurs (interrupt is enabled and no handler
is installed, which usually indicates a bug), then the default action
is to reset the device by jumping to the reset vector. You can
override this by supplying a function named BADISR_vect which should
be defined with ISR() as such. (The name BADISR_vect is actually an
alias for __vector_default. The latter must be used inside assembly
code in case is not included.)
I ran in the same situation right now, but since I don't have a high reputation on stackoverflow, I can not vote.
here is a snippet of my initialization procedure that caused this problem to me:
void USART_Init()
{
cli();
/* Set baud rate */
UBRR0H = (uint8_t)(BAUD_PRESCALE>>8);
UBRR0L = (uint8_t)BAUD_PRESCALE;
/* Enable receiver and transmitter */
UCSR0B |= (1<<RXEN0)|(1<<TXEN0);
/* Set frame format: 8data, 1stop bit 8N1 => 86uS for a byte*/
UCSR0C |= (1<<UCSZ01)|(1<<UCSZ00);
/*enable Rx and Tx Interrupts*/
UCSR0B |= (1 << RXCIE0) | (1 << TXCIE0); //<- this was the problem
/*initialize the RingBuffer*/
RingBuffer_Init(&RxBuffer);
sei();
}
The problem was that I initially used interrupt based transmission, but later on I have changed the design and went for 10ms polling for Tx sequence, and forgotten to change this line as well in the init procedure.
Thanks very much for pointing this out Peter Gibson.