mirror of
https://github.com/oliverschmidt/contiki.git
synced 2024-12-23 01:29:33 +00:00
98 lines
3.2 KiB
C
98 lines
3.2 KiB
C
/*
|
|
* Copyright (c) 2010, Mariano Alvira <mar@devl.org> and other contributors
|
|
* to the MC1322x project (http://mc1322x.devl.org)
|
|
* All rights reserved.
|
|
*
|
|
* Redistribution and use in source and binary forms, with or without
|
|
* modification, are permitted provided that the following conditions
|
|
* are met:
|
|
* 1. Redistributions of source code must retain the above copyright
|
|
* notice, this list of conditions and the following disclaimer.
|
|
* 2. Redistributions in binary form must reproduce the above copyright
|
|
* notice, this list of conditions and the following disclaimer in the
|
|
* documentation and/or other materials provided with the distribution.
|
|
* 3. Neither the name of the Institute nor the names of its contributors
|
|
* may be used to endorse or promote products derived from this software
|
|
* without specific prior written permission.
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
|
|
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
|
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
|
|
* ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
|
|
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
|
|
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
|
|
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
|
|
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
|
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
|
|
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
|
|
* SUCH DAMAGE.
|
|
*
|
|
* This file is part of libmc1322x: see http://mc1322x.devl.org
|
|
* for details.
|
|
*
|
|
*
|
|
*/
|
|
|
|
#include <mc1322x.h>
|
|
#include <stdlib.h>
|
|
#include "tmr.h"
|
|
|
|
/* Initialize timer. This just counts and interrupts, doesn't drive an output.
|
|
timer_num = 0, 1, 2, 3
|
|
rate = desired rate in Hz,
|
|
enable_int = whether to enable an interrupt on every cycle
|
|
Returns actual timer rate. */
|
|
uint32_t timer_setup_ex(int timer_num, uint32_t rate, int enable_int)
|
|
{
|
|
uint32_t actual_rate;
|
|
volatile struct TMR_struct *timer = TMR_ADDR(timer_num);
|
|
int log_divisor = 0;
|
|
uint32_t period;
|
|
|
|
/* Turn timer off */
|
|
TMR0->ENBL &= ~(1 << timer_num);
|
|
|
|
/* Calculate optimal rate */
|
|
for (log_divisor = 0; log_divisor < 8; log_divisor++)
|
|
{
|
|
int denom = (rate * (1 << log_divisor));
|
|
period = (REF_OSC + denom/2) / denom;
|
|
if (period <= 65535)
|
|
break;
|
|
}
|
|
if (log_divisor >= 8)
|
|
{
|
|
period = 65535;
|
|
log_divisor = 7;
|
|
}
|
|
|
|
if (period < 2) period = 2;
|
|
|
|
actual_rate = REF_OSC / (period * (1 << log_divisor));
|
|
|
|
/* Set up timer */
|
|
|
|
timer->LOAD = 0;
|
|
timer->CMPLD1 = (period - 1);
|
|
timer->COMP1 = timer->CMPLD1;
|
|
timer->CNTR = timer->LOAD;
|
|
timer->SCTRL = 0;
|
|
timer->CSCTRLbits = (struct TMR_CSCTRL) {
|
|
.CL1 = 0x01, // Reload COMP1 when COMP1 matches
|
|
};
|
|
timer->CTRLbits = (struct TMR_CTRL) {
|
|
.COUNT_MODE = 1, // Count rising edge of primary source
|
|
.PRIMARY_CNT_SOURCE = 8 + log_divisor, // Peripheral clock divided by (divisor)
|
|
.LENGTH = 1, // At compare, reset to LOAD
|
|
};
|
|
|
|
TMR0->ENBL |= (1 << timer_num);
|
|
|
|
if (enable_int) {
|
|
enable_irq(TMR);
|
|
timer->SCTRLbits.TCFIE = 1;
|
|
}
|
|
|
|
return actual_rate;
|
|
}
|