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112 lines
3.0 KiB
112 lines
3.0 KiB
/* |
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* Copyright (C) Siddharth Bharat Purohit 2017 |
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* This file is free software: you can redistribute it and/or modify it |
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* under the terms of the GNU General Public License as published by the |
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* Free Software Foundation, either version 3 of the License, or |
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* (at your option) any later version. |
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* |
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* This file is distributed in the hope that it will be useful, but |
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* WITHOUT ANY WARRANTY; without even the implied warranty of |
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. |
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* See the GNU General Public License for more details. |
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* |
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* You should have received a copy of the GNU General Public License along |
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* with this program. If not, see <http://www.gnu.org/licenses/>. |
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*/ |
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/* |
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High Resolution Timer code. This provides support for 32 and 64 bit |
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returns for micros and millis functions |
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*/ |
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#include "ch.h" |
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#include "hal.h" |
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#include "hrt.h" |
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#include <stdint.h> |
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#pragma GCC optimize("O2") |
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/* |
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we have 4 possible configurations of boards, made up of boards that |
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have the following properties: |
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CH_CFG_ST_RESOLUTION = 16 or 32 |
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CH_CFG_ST_FREQUENCY = 1000 or 1000000 |
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To keep as much code in common as possible we create a function |
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system_time_u32_us() for all boards which gives system time since |
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boot in microseconds, and which wraps at 0xFFFFFFFF. |
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On top of this base function we build get_systime_us32() which has |
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the same property, but which also maintains timer_base_us64 to allow |
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for micros64() |
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*/ |
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#if CH_CFG_ST_RESOLUTION == 16 |
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static uint32_t system_time_u32_us(void) |
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{ |
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systime_t now = chVTGetSystemTimeX(); |
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#if CH_CFG_ST_FREQUENCY != 1000000U |
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now *= 1000000U/CH_CFG_ST_FREQUENCY; |
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#endif |
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static systime_t last_systime; |
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static uint32_t timer_base_us32; |
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uint16_t dt = now - last_systime; |
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last_systime = now; |
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timer_base_us32 += dt; |
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return timer_base_us32; |
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} |
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#elif CH_CFG_ST_RESOLUTION == 32 |
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static uint32_t system_time_u32_us(void) |
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{ |
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systime_t now = chVTGetSystemTimeX(); |
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#if CH_CFG_ST_FREQUENCY != 1000000U |
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now *= 1000000U/CH_CFG_ST_FREQUENCY; |
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#endif |
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return now; |
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} |
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#else |
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#error "unsupported timer resolution" |
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#endif |
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// offset for micros64() |
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static uint64_t timer_base_us64; |
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static uint32_t get_systime_us32(void) |
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{ |
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static uint32_t last_us32; |
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uint32_t now = system_time_u32_us(); |
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if (now < last_us32) { |
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const uint64_t dt_us = 0x100000000ULL; |
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timer_base_us64 += dt_us; |
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} |
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last_us32 = now; |
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return now; |
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} |
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/* |
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for the exposed functions we use chSysGetStatusAndLockX() to prevent |
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an interrupt changing the globals while allowing this call from any |
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context |
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*/ |
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uint64_t hrt_micros64() |
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{ |
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syssts_t sts = chSysGetStatusAndLockX(); |
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uint32_t now = get_systime_us32(); |
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uint64_t ret = timer_base_us64 + now; |
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chSysRestoreStatusX(sts); |
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return ret; |
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} |
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uint32_t hrt_micros32() |
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{ |
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syssts_t sts = chSysGetStatusAndLockX(); |
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uint32_t ret = get_systime_us32(); |
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chSysRestoreStatusX(sts); |
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return ret; |
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} |
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uint32_t hrt_millis32() |
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{ |
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return (uint32_t)(hrt_micros64() / 1000U); |
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}
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