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Implement rtimers for ADuCRF101

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This commit is contained in:
Jim Paris 2014-06-27 18:19:05 -04:00
parent c8716f4d57
commit ad141b00fb
5 changed files with 96 additions and 15 deletions
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103
cpu/arm/aducrf101/rtimer-arch.c
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@ -35,25 +35,104 @@
* \author Jim Paris <jim.paris@rigado.com>
*/
#include <contiki.h>
#include "rtimer-arch.h"
#include "aducrf101-contiki.h"
/* rtimer on the ADuCRF101 is implemented with the "wakeup" timer.
(timer 2). It should be clocked from an external crystal,
but if that doesn't seem to be present, this code will select the
imprecise internal 32.768 KHz oscillator instead. */
static void
_timer2_enable(int enable)
{
T2CON_ENABLE_BBA = enable;
clock_time_t now = clock_time();
while(T2STA_CON_BBA) {
/* Synchronizing settings may fail if the chosen clock isn't running;
wait no more than 1ms for it */
if((clock_time() - now) > (CLOCK_SECOND / 1000)) {
break;
}
}
}
static uint32_t
_timer2_val(void)
{
/* This is atomic because the FREEZE bit is set in T2CON. */
uint32_t now;
now = pADI_WUT->T2VAL0;
now |= pADI_WUT->T2VAL1 << 16;
return now;
}
static uint32_t
_timer2_measure_freq(void)
{
const int test_usec = 10000;
uint32_t now = _timer2_val();
clock_delay_usec(test_usec);
return (_timer2_val() - now) * (1000000 / test_usec);
}
void
rtimer_arch_init(void)
{
uint32_t freq;
const char *timer = "LFXTAL";
_timer2_enable(0);
pADI_WUT->T2CON = T2CON_PRE_DIV1 | T2CON_MOD_FREERUN | T2CON_FREEZE_EN |
T2CON_WUEN_EN;
/* Try 32.768 KHz crystal */
pADI_WUT->T2CON |= T2CON_CLK_LFXTAL;
_timer2_enable(1);
freq = _timer2_measure_freq();
if(freq < 20000 || freq > 40000) {
/* No good; use 32.768 KHz internal oscillator */
_timer2_enable(0);
pADI_WUT->T2CON &= ~T2CON_CLK_MSK;
pADI_WUT->T2CON |= T2CON_CLK_LFOSC;
_timer2_enable(1);
freq = _timer2_measure_freq();
timer = "LFOSC";
}
printf("Using %s for rtimer (%ld Hz)\n", timer, freq);
/* Enable interrupt in NVIC, but disable in WUT for now. */
pADI_WUT->T2IEN = 0;
NVIC_EnableIRQ(WUT_IRQn);
}
/*---------------------------------------------------------------------------*/
void
rtimer_arch_schedule(rtimer_clock_t t)
{
}
/*---------------------------------------------------------------------------*/
void
rtimer_arch_set(rtimer_clock_t t)
{
}
/*---------------------------------------------------------------------------*/
rtimer_clock_t
rtimer_arch_now(void)
{
return 0;
/* This is atomic because the FREEZE bit is set in T2CON. */
return _timer2_val();
}
void
rtimer_arch_schedule(rtimer_clock_t t)
{
uint32_t now = _timer2_val();
/* Minimum of 5 wakeup timer ticks */
if((int32_t)(t - now) < 5) {
t = now + 5;
}
/* Set T2WUFB to match at target time */
T2IEN_WUFB_BBA = 0;
pADI_WUT->T2WUFB0 = (t & 0xffff);
pADI_WUT->T2WUFB1 = (t >> 16);
T2IEN_WUFB_BBA = 1;
}
void
WakeUp_Int_Handler(void)
{
/* clear interrupt */
T2CLRI_WUFB_BBA = 1;
/* disable T2WUFB match */
T2IEN_WUFB_BBA = 0;
rtimer_run_next();
}