Can't Get an Interrupt to Execute

RE: Can't Get an Interrupt to Execute

Don_Pez — Tue, 02 Jun 2020 20:36:38 GMT

Brilliant gentlemen! This was the problem. I changed the interrupt number to that in the file you found (good work) and was able to get it to interrupt. I also was turning the LED on in the ISR using the pin state, which was triggered by a rising edge, so the LED was always on...duh. I fixed that and now it works.

Thanks for all your help, both of you! You saved the day.

Don

DG Devices

RE: Can't Get an Interrupt to Execute

Dmitry — Tue, 02 Jun 2020 19:12:08 GMT

hmolesworth is right. Look at digitalWrite() and digitalRead() in wiring_digital.c, you can see that GPIO pin number passes through remapping:

ulPin = g_ADigitalPinMap[ulPin];

Pin mapping is defined in variants subdirectory, for BleNANO it will be in variant.cpp, where GPIO 2 corresponds to P0.10 in Nordic numeration. I don't know exactly which variant corresponds to your board, but pin numbering in Arduino IDE and Nordic SDK files are definitely different.

RE: Can't Get an Interrupt to Execute

hmolesworth — Tue, 02 Jun 2020 17:39:33 GMT

There are actually 48 i/o pins, not 32; nRF52840 has 2 i/o ports P0 and P1, nRF52832 has only 1 (P0).

/**
 * @brief Function for extracting port and the relative pin number from the absolute pin number.
 *
 * @param[in,out] p_pin Pointer to the absolute pin number overriden by the pin number that is relative to the port.
 *
 * @return Pointer to port register set.
 */
__STATIC_INLINE NRF_GPIO_Type * nrf_gpio_pin_port_decode(uint32_t * p_pin)
{
    NRFX_ASSERT(*p_pin < NUMBER_OF_PINS);
#if (GPIO_COUNT == 1)
    return NRF_P0;
#else
    if (*p_pin < P0_PIN_NUM)
    {
        return NRF_P0;
    }
    else
    {
        *p_pin = *p_pin & (P0_PIN_NUM - 1);
        return NRF_P1;
    }
#endif
}

I'm not sure I'm helping here, I have no idea what those non-Nordic definitions are doing in relation to mapping pins, such as pinmode() for example, if no code is posted. Maybe others are familiar with them ..

RE: Can't Get an Interrupt to Execute

Don_Pez — Tue, 02 Jun 2020 16:47:13 GMT

But If D2 works when directly connected to the LED, then shouldn't it work when used to trigger an external interrupt? A pin is a pin, isn't it? If the mapping were different, it would cause serious problems. In my code above (two posts ago) I used D2 (GPIO2) as an interrupt and it doesn't work.

I don't think there even is a "GPIO39". I tried this:

int epin = 39;
void setup() {
  pinMode(LED_BUILTIN, OUTPUT);                       //set built-in LED pin as output
  pinMode(epin, INPUT);                                  //set pin 39 as pullup input
}

void loop() {
 int pin39 = 0;
  pin39 = digitalRead(epin);
  if(pin39)
    digitalWrite(LED_BUILTIN, HIGH);
    else
      digitalWrite(LED_BUILTIN, LOW);
}

And nothing happens with any pin. GPIO numbers are only supposed to be 0 to 31.

Regardless of what is mapped to what, how can D2 operate the LED directly, but not generate an interrupt on the same GPIO?

Don

DG Devices

RE: Can't Get an Interrupt to Execute

hmolesworth — Tue, 02 Jun 2020 16:19:06 GMT

Post the code for pinmode, digitalRead and digitalWrite, maybe there is some mapping there. The Nordic functions such as nrf_gpio_cfg_output deal with nRF52840 pin numbers P0.02 is pin 2 in that notation. GPIO39 is Nordic nRF52840 pin P1.11

RE: Can't Get an Interrupt to Execute

Don_Pez — Tue, 02 Jun 2020 16:10:03 GMT

I still don't understand. If I run this code:

int epin = 2;
void setup() {
  nrf_gpio_cfg_output(LED_BUILTIN);                       //set built-in LED pin as output
  nrf_gpio_cfg_input(epin, NRF_GPIO_PIN_PULLUP);  //set pin 2 as pullup input
}

void loop() {
 int pin2 = 0;
  pin2 = digitalRead(epin);
  if(pin2)
    digitalWrite(LED_BUILTIN, HIGH);
    else
      digitalWrite(LED_BUILTIN, LOW);
}

The LED will be on. If I connect pin D2 to ground, the LED turns off, if I disconnect it, it turns back on. No other GPIO pin will affect the LED but D2. Doesn't that mean that D2 is mapped to GPIO 2? I don't understand.

If D2 is mapped to P1.11, then what GPIO number do I use? The GPIO number is an integer, not a P number.

If I use the Arduino method I get the same result:

int epin = 2;
void setup() {
  pinMode(LED_BUILTIN, OUTPUT);                       //set built-in LED pin as output
  pinMode(epin, INPUT);                                  //set pin 2 as pullup input
}

void loop() {
 int pin2 = 0;
  pin2 = digitalRead(epin);
  if(pin2)
    digitalWrite(LED_BUILTIN, HIGH);
    else
      digitalWrite(LED_BUILTIN, LOW);
}

I don't understand what you're telling me. The wiring schematic you refer to shows D2 connected to GPIO39, but GPIO's only are supposed to go to 31. How can this be?

All I need is to have six input pins that I can use for external interrupts. If someone can tell me what pins to use and what GPIO numbers to use, that will get me by.

Don

DG Devices

RE: Can't Get an Interrupt to Execute

hmolesworth — Tue, 02 Jun 2020 15:30:20 GMT

"D2" is P1.11 on the nRF52840 on the Nano 33 BLE, yet "epin" is defined as "2" which is a different pin, P0.02 which happens to be used on the Nano for AIN0 and SCL.

The red/green/blue LEDs are active-low, so this code turns those LEDs off, not on (Yellow is active high, edit):

  digitalWrite(LED, HIGH);

This is the NANO33BLE_V2.0 schematic I referred to, in case I missed something in the posts above, hope this helps.

RE: Can't Get an Interrupt to Execute

Don_Pez — Tue, 02 Jun 2020 15:26:04 GMT

I had originally tried the Arduino interrupt method. I tried it again today to verify. I even tried explicitly using the numeral "2" for the pin. You can't get any simpler than this...

void setup(){
Serial.begin(9600); //start display serial
while (!Serial);

attachInterrupt(2, estring_ISR, RISING);
}

void loop(){
}

void estring_ISR(void){
Serial.println("interrupt occurred");
}

When run, this code refuses to interrupt when a signal is applied to pin 2 (literally jumping pin 2 to 3.3V and to ground). I know the pin is not bad because I can use it elsewhere just fine.

It's as if I'm using the wrong pin. I looked over the Arduino core code that you posted and it looks like my code should work. I can't figure it out.

Don

RE: Can't Get an Interrupt to Execute

Dmitry — Tue, 02 Jun 2020 07:34:33 GMT

The handler for GPIOTE is defined in arduino core and used for attachInterrupt/detachInterrupt. You cannot redefine it without changing core sources. I think you can use EGU peripheral to pass GPIOTE event to EGU interrupt handler that is not defined by core.

RE: Can't Get an Interrupt to Execute

Don_Pez — Mon, 01 Jun 2020 15:15:18 GMT

The Arduino compiler is based on C++, but I can't get extern "C" to work at all. I am dead in the water and I need to get this product prototype running soon. No other development board has a small enough profile to fit in my application.

Apparently the handler isn't getting recognized (though I get no errors). Isn't there any other way of making the compiler execute the ISR?

Don

RE: Can't Get an Interrupt to Execute

Dmitry — Mon, 01 Jun 2020 09:19:27 GMT

Do you use Arduino IDE? AFAIK its language is a sort of C++, maybe you just have to add extern "C" { ... } around your handler.

RE: Can't Get an Interrupt to Execute

Don_Pez — Sun, 31 May 2020 18:41:30 GMT

I had another Arduino Nano 33 BLE Nano, which also runs on a 52840. I tried downloading the same two programs with the same results today. So I don't think it is a faulty processor.

Don

RE: Can't Get an Interrupt to Execute

Don_Pez — Sun, 31 May 2020 15:58:33 GMT

I cut the code down to the bare minimum and ran it. This is literally the entire program now:

#include <nrf.h>
#include "nrf_timer.h"
#include "nrf_gpio.h"

volatile uint32_t last_ecount = 0;                //last count values
const int epin = 2;                               //board pin D2, signal from E-wave
int LED = LED_BUILTIN;                            //built-in orange LED for debug
static void gpio_initialize(void);

void setup() {  

  nrf_gpio_cfg_output(LED);                       //set built-in LED pin as output
  nrf_gpio_cfg_input(epin, NRF_GPIO_PIN_PULLUP);  //set pin 2 as pullup input
   
  NVIC_EnableIRQ(GPIOTE_IRQn);                    //enable interrupts
  NRF_GPIOTE->CONFIG[0] = 0x00010201;             //low-to-high, pin2, event mode
  NRF_GPIOTE->INTENSET = 0x00000001;              //enable IN[0]   
  
  NRF_TIMER1->TASKS_STOP = 1;
  NRF_TIMER1->MODE = 0;
  NRF_TIMER1->BITMODE = 3;                        //timer1 32-bit mode
  NRF_TIMER1->PRESCALER = 0;                      //use full system clock for timer1: 16 MHz
  NRF_TIMER1->TASKS_CLEAR = 1;
  NRF_TIMER1->CC[0] = 0;                          //zero timer1
  NRF_TIMER1->TASKS_START = 1;                    //start timer1
}

void loop() {
  
}
   
void GPIOTE_IRQHandler(void){                     //interrupts
  uint32_t count = 0;
  int avcount = 0;
  
  digitalWrite(LED, HIGH);
   
  if(NRF_GPIOTE->EVENTS_IN[0] == 1){              //filter interrupt for E-wave
    NRF_GPIOTE->EVENTS_IN[0] = 0;                 //clear interrupt flag
    NRF_TIMER1->TASKS_CAPTURE[0] = 1;             //capture timer1 value in CC0
    count = NRF_TIMER1->CC[0] - last_ecount;      //time elaspsed for one wave (CC0)
    last_ecount = count;                          //reset for next count
  }
}

When I connect pin2 (epin = 2) to ground or to 3.3V I get nothing on the LED.

However, when I move the LED output driver from the ISR to the loop() and control it directly with epin like this:

#include <nrf.h>
#include "nrf_timer.h"
#include "nrf_gpio.h"

volatile uint32_t last_ecount = 0;                //last count values
const int epin = 2;                               //board pin D2, signal from E-wave
int LED = LED_BUILTIN;                            //built-in orange LED for debug
static void gpio_initialize(void);

void setup() {  
  nrf_gpio_cfg_output(LED);                       //set built-in LED pin as output
  nrf_gpio_cfg_input(epin, NRF_GPIO_PIN_PULLUP);  //set pin 2 as pullup input
   
  NVIC_EnableIRQ(GPIOTE_IRQn);                    //enable interrupts
  NRF_GPIOTE->CONFIG[0] = 0x00010201;             //low-to-high, pin2, event mode
  NRF_GPIOTE->INTENSET = 0x00000001;              //enable IN[0]   
  
  NRF_TIMER1->TASKS_STOP = 1;
  NRF_TIMER1->MODE = 0;
  NRF_TIMER1->BITMODE = 3;                        //timer1 32-bit mode
  NRF_TIMER1->PRESCALER = 0;                      //use full system clock for timer1: 16 MHz
  NRF_TIMER1->TASKS_CLEAR = 1;
  NRF_TIMER1->CC[0] = 0;                          //zero timer1
  NRF_TIMER1->TASKS_START = 1;                    //start timer1
}

void loop() {
  int pin2 = 0;
  pin2 = digitalRead(epin);
  if(pin2)
    digitalWrite(LED, HIGH);
    else
      digitalWrite(LED, LOW);
}
   
void GPIOTE_IRQHandler(void){                     //string interrupts
  uint32_t count = 0;
  int avcount = 0;
   
  if(NRF_GPIOTE->EVENTS_IN[0] == 1){              //filter interrupt for E-string
    NRF_GPIOTE->EVENTS_IN[0] = 0;                 //clear interrupt flag
    NRF_TIMER1->TASKS_CAPTURE[0] = 1;             //capture timer1 value in CC0
    count = NRF_TIMER1->CC[0] - last_ecount;      //time elaspsed for one vibration (CC0)
    last_ecount = count;                          //reset for next count
  }
}

I get a lit LED, which I can turn off by connecting pin2 to ground. No other input pin does this but pin2.

I don't understand.

Don

RE: Can't Get an Interrupt to Execute

Dmitry — Sun, 31 May 2020 09:59:59 GMT

Maybe you could put the whole project here? I don't see anything wrong in your configuration.

[quote userid="90729" url="~/f/nordic-q-a/61961/can-t-get-an-interrupt-to-execute/252524"]Another interesting thing is that I can't get it to interrupt even if I explicitly set NRF_GPIOTE->EVENTS_IN[0] = 1; in the loop code.[/quote]

This won't work, you can only clear EVENTS register by software, not set.

RE: Can't Get an Interrupt to Execute

Don_Pez — Sat, 30 May 2020 21:43:36 GMT

You are right about making last_ecount global, but I haven't gotten that far yet. I still need to interrupt.

I verify the interrupt by putting

digitalWrite(LED, HIGH); (Arduino method)

Inside the ISR. It never lights up when I connect pin2 to 3.3V or ground. I also tried code to light the LED directly with pin2, which works, so I know my GPIO number is correct (2) and that the LED is functioning properly.

Another interesting thing is that I can't get it to interrupt even if I explicitly set

NRF_GPIOTE->EVENTS_IN[0] = 1;

in the loop code.

So you can see my dilemma. Is there some other enable for interrupts besides INTENSET or NVIC_EnableIRQ(GPIOTE_IRQn)?

Don

RE: Can't Get an Interrupt to Execute

Dmitry — Sat, 30 May 2020 20:57:20 GMT

How did you found that your interrupt handler is not called? Did you set a breakpoint?

The hardware seems to be configured ok. What I can see - last_ecount and count are defined inside an interrupt handler and will be zeroed every time the handler is called, they're probably will be optimized out by the compiler as well. You need to define last_ecount as global variable outside your handler.

RE: Can't Get an Interrupt to Execute

Don_Pez — Sat, 30 May 2020 15:29:27 GMT

No errors? Should I assume that the Nordic chip is faulty?

Don

DG Devices