[En-Nut-Discussion] Using the Periodic Interval Timer on the Ethernut 5 without Nut/OS

[Dusan Ferbas]

Hi Robin,

I am not familiar with SAM9 platform and I do not know your conf  file.
I suggest to compile a simple app example with Ethernut50f.conf and 
compare map file to your project map file.
Mainly if routines from nut/arch/arm/board/ethernut5.c are present, 
which confirms a correct LD script was applied.

Dusan Ferbas

Solar Monitor s.r.o. | Žižkova 562 | 511 01 Turnov | Czech Republic
Tel.: +420 481 313 661 | Mobile: +420 603 147 723

On 29.11.2021 13:59, Robin Leinauer wrote:
> Hello everyone,
>
>
> I'm trying to use the Periodic Interval Timer on the Ethernut 5.0 F without Nut/OS.
>
> I have set up the project according to the following guide: http://www.ethernut.de/de/hardware/enut3/noos.html.
>
> This is my code:
>
> //---------------------------------------------------------------------------------------------------------------------------------------
>
> #include <toolchain.h>
>
> #define MCK 90317000
> #define LED_PIN 28
>
> volatile unsigned int timer_ticks = 0;
>
> void spurious_entry(void)__attribute__((naked));
> void spurious_entry(void)
> {
>      IRQ_ENTRY();
>      IRQ_EXIT();
> }
>
> void timer_tick(void)__attribute__((naked));
> void timer_tick(void)
> {
>      IRQ_ENTRY();
>
>      timer_ticks++;
>      inr(PIT_PIVR);                                              // acknowledge timer interrupt
>
>      IRQ_EXIT();
> }
>
> void init_timer(void)
> {
>      outr(PIT_MR, (MCK / (16 * 1000) - 1));
>
>      outr(AIC_IDCR, _BV(SYSC_ID));                               // disable interrupt
>      outr(AIC_SVR(SYSC_ID), (unsigned int)timer_tick);           // set interrupt handler
>      outr(AIC_SMR(SYSC_ID), AIC_SRCTYPE_INT_LEVEL_SENSITIVE);    // define priority
>      outr(AIC_ICCR, _BV(SYSC_ID));                               // clear interrupt
>
>      outr(PIT_MR, inr(PIT_MR) | PIT_PITEN | PIT_PITIEN);         // enable timer and timer interrupt
>
>      outr(AIC_IECR, _BV(SYSC_ID));                               // enable interrupt
>      inr(PIT_PIVR);
> }
>
> void init_led(unsigned int pin)
> {
>      outr(PIOA_OER, _BV(pin));
>      outr(PIOA_PER, _BV(pin));
> }
>
> void led_on(unsigned int pin)
> {
>      outr(PIOA_CODR, _BV(pin));
> }
>
> void led_off(unsigned int pin)
> {
>      outr(PIOA_SODR, _BV(pin));
> }
>
> void NutInit(void)
> {
>      outr(AIC_SPU, (unsigned int)spurious_entry);
>      outr(AIC_IDCR, 0xffffffff);                                 // disable all interrupts
>      outr(AIC_ICCR, 0xffffffff);                                 // clear all interrupts
>      init_timer();
>      init_led(LED_PIN);
>
>      for(;;)
>      {
>          led_on(LED_PIN);
>          if(timer_ticks > 0)break;
>      }
>
>      // is never reached
>      led_off(LED_PIN);
>      for(;;);
> }
> //---------------------------------------------------------------------------------------------------------------------------------------
> Everything compiles without errors, but unfortunately the first for-loop never exited during execution, the led never turns off.
> What am I doing wrong?
> I'm using an Ethernut 5.0 F and loading the image via TFTP.
>
>
> Thanks and best regards
>
> Robin
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