ardupilot/libraries/AP_HAL_ChibiOS/hwdef/common/hrt.c

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/*
* Copyright (C) Siddharth Bharat Purohit 2017
* This file is free software: you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This file is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
* See the GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program. If not, see <http://www.gnu.org/licenses/>.
*/
// High Resolution Timer
#include "ch.h"
#include "hal.h"
#include "hrt.h"
#include <stdint.h>
/*
* HRT GPT configuration
*/
//static void hrt_cb(GPTDriver*);
static uint64_t timer_base = 0;
static const GPTConfig hrtcfg = {
1000000, /* 1MHz timer clock.*/
NULL, /* Timer callback.*/
0,
0
};
void hrt_init()
{
gptStart(&HRT_TIMER, &hrtcfg);
gptStartContinuous(&HRT_TIMER, 0xFFFF);
}
uint64_t hrt_micros()
{
static volatile uint64_t last_micros = 0;
static volatile uint64_t micros;
syssts_t sts = chSysGetStatusAndLockX();
micros = timer_base + (uint64_t)gptGetCounterX(&HRT_TIMER);
// we are doing this to avoid an additional interupt routing
// since we are definitely going to get called atleast once in
// a full timer period
if(last_micros > micros) {
timer_base += 0x10000;
micros += 0x10000;
}
last_micros = micros;
chSysRestoreStatusX(sts);
return micros;
}
/*
static void hrt_cb(GPTDriver* gptd)
{
timer_base += 0x10000;
}
*/