139 lines
4.1 KiB
C
139 lines
4.1 KiB
C
/**
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* Copyright (c) 2014, Analog Devices, Inc. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted (subject to the limitations in the
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* disclaimer below) provided that the following conditions are met:
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*
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* - Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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*
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* - Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the
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* distribution.
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*
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* - Neither the name of Analog Devices, Inc. nor the names of its
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* contributors may be used to endorse or promote products derived
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* from this software without specific prior written permission.
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*
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* NO EXPRESS OR IMPLIED LICENSES TO ANY PARTY'S PATENT RIGHTS ARE
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* GRANTED BY THIS LICENSE. THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT
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* HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED
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* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
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* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
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* BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
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* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
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* OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN
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* IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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/**
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* \author Jim Paris <jim.paris@rigado.com>
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*/
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#include <contiki.h>
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#include "rtimer-arch.h"
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#include "aducrf101-contiki.h"
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/* rtimer on the ADuCRF101 is implemented with the "wakeup" timer.
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(timer 2). It should be clocked from an external crystal,
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but if that doesn't seem to be present, this code will select the
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imprecise internal 32.768 KHz oscillator instead. */
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static void
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_timer2_enable(int enable)
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{
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T2CON_ENABLE_BBA = enable;
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clock_time_t now = clock_time();
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while(T2STA_CON_BBA) {
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/* Synchronizing settings may fail if the chosen clock isn't running;
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wait no more than 1ms for it */
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if((clock_time() - now) > (CLOCK_SECOND / 1000)) {
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break;
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}
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}
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}
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static uint32_t
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_timer2_val(void)
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{
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/* This is atomic because the FREEZE bit is set in T2CON. */
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uint32_t now;
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now = pADI_WUT->T2VAL0;
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now |= pADI_WUT->T2VAL1 << 16;
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return now;
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}
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static uint32_t
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_timer2_measure_freq(void)
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{
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const int test_usec = 10000;
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uint32_t now = _timer2_val();
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clock_delay_usec(test_usec);
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return (_timer2_val() - now) * (1000000 / test_usec);
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}
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void
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rtimer_arch_init(void)
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{
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uint32_t freq;
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const char *timer = "LFXTAL";
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_timer2_enable(0);
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pADI_WUT->T2CON = T2CON_PRE_DIV1 | T2CON_MOD_FREERUN | T2CON_FREEZE_EN |
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T2CON_WUEN_EN;
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/* Try 32.768 KHz crystal */
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pADI_WUT->T2CON |= T2CON_CLK_LFXTAL;
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_timer2_enable(1);
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freq = _timer2_measure_freq();
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if(freq < 20000 || freq > 40000) {
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/* No good; use 32.768 KHz internal oscillator */
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_timer2_enable(0);
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pADI_WUT->T2CON &= ~T2CON_CLK_MSK;
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pADI_WUT->T2CON |= T2CON_CLK_LFOSC;
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_timer2_enable(1);
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freq = _timer2_measure_freq();
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timer = "LFOSC";
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}
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printf("Using %s for rtimer (%ld Hz)\n", timer, freq);
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/* Enable interrupt in NVIC, but disable in WUT for now. */
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pADI_WUT->T2IEN = 0;
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NVIC_EnableIRQ(WUT_IRQn);
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}
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rtimer_clock_t
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rtimer_arch_now(void)
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{
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/* This is atomic because the FREEZE bit is set in T2CON. */
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return _timer2_val();
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}
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void
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rtimer_arch_schedule(rtimer_clock_t t)
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{
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uint32_t now = _timer2_val();
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/* Minimum of 5 wakeup timer ticks */
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if((int32_t)(t - now) < 5) {
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t = now + 5;
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}
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/* Set T2WUFB to match at target time */
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T2IEN_WUFB_BBA = 0;
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pADI_WUT->T2WUFB0 = (t & 0xffff);
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pADI_WUT->T2WUFB1 = (t >> 16);
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T2IEN_WUFB_BBA = 1;
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}
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void
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WakeUp_Int_Handler(void)
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{
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/* clear interrupt */
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T2CLRI_WUFB_BBA = 1;
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/* disable T2WUFB match */
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T2IEN_WUFB_BBA = 0;
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rtimer_run_next();
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}
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