Marcell Rausch / mbed-dev-no-serial

mbed library sources. Supersedes mbed-src. removed serial

Fork of mbed-dev by mbed official

targets/TARGET_Maxim/TARGET_MAX32625/us_ticker.c@158:aa577577efe0, 2017-02-13 (annotated)

Committer:
mrcrsch
Date:
Mon Feb 13 14:26:36 2017 +0000
Revision:
158:aa577577efe0
Parent:
150:02e0a0aed4ec 
removed stdio and serial to reduce size

Who changed what in which revision?

UserRevisionLine numberNew contents of line
<> 150:02e0a0aed4ec 1 /*******************************************************************************
<> 150:02e0a0aed4ec 2 * Copyright (c) 2016 Maxim Integrated Products, Inc., All Rights Reserved.
<> 150:02e0a0aed4ec 3 *
<> 150:02e0a0aed4ec 4 * Permission is hereby granted, free of charge, to any person obtaining a
<> 150:02e0a0aed4ec 5 * copy of this software and associated documentation files (the "Software"),
<> 150:02e0a0aed4ec 6 * to deal in the Software without restriction, including without limitation
<> 150:02e0a0aed4ec 7 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
<> 150:02e0a0aed4ec 8 * and/or sell copies of the Software, and to permit persons to whom the
<> 150:02e0a0aed4ec 9 * Software is furnished to do so, subject to the following conditions:
<> 150:02e0a0aed4ec 10 *
<> 150:02e0a0aed4ec 11 * The above copyright notice and this permission notice shall be included
<> 150:02e0a0aed4ec 12 * in all copies or substantial portions of the Software.
<> 150:02e0a0aed4ec 13 *
<> 150:02e0a0aed4ec 14 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
<> 150:02e0a0aed4ec 15 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
<> 150:02e0a0aed4ec 16 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
<> 150:02e0a0aed4ec 17 * IN NO EVENT SHALL MAXIM INTEGRATED BE LIABLE FOR ANY CLAIM, DAMAGES
<> 150:02e0a0aed4ec 18 * OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
<> 150:02e0a0aed4ec 19 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
<> 150:02e0a0aed4ec 20 * OTHER DEALINGS IN THE SOFTWARE.
<> 150:02e0a0aed4ec 21 *
<> 150:02e0a0aed4ec 22 * Except as contained in this notice, the name of Maxim Integrated
<> 150:02e0a0aed4ec 23 * Products, Inc. shall not be used except as stated in the Maxim Integrated
<> 150:02e0a0aed4ec 24 * Products, Inc. Branding Policy.
<> 150:02e0a0aed4ec 25 *
<> 150:02e0a0aed4ec 26 * The mere transfer of this software does not imply any licenses
<> 150:02e0a0aed4ec 27 * of trade secrets, proprietary technology, copyrights, patents,
<> 150:02e0a0aed4ec 28 * trademarks, maskwork rights, or any other form of intellectual
<> 150:02e0a0aed4ec 29 * property whatsoever. Maxim Integrated Products, Inc. retains all
<> 150:02e0a0aed4ec 30 * ownership rights.
<> 150:02e0a0aed4ec 31 *******************************************************************************
<> 150:02e0a0aed4ec 32 */
<> 150:02e0a0aed4ec 33
<> 150:02e0a0aed4ec 34 #include <stddef.h>
<> 150:02e0a0aed4ec 35 #include "mbed_error.h"
<> 150:02e0a0aed4ec 36 #include "us_ticker_api.h"
<> 150:02e0a0aed4ec 37 #include "PeripheralNames.h"
<> 150:02e0a0aed4ec 38 #include "tmr.h"
<> 150:02e0a0aed4ec 39
<> 150:02e0a0aed4ec 40 #define US_TIMER MXC_TMR0
<> 150:02e0a0aed4ec 41 #define US_TIMER_IRQn TMR0_0_IRQn
<> 150:02e0a0aed4ec 42
<> 150:02e0a0aed4ec 43 static int us_ticker_inited = 0;
<> 150:02e0a0aed4ec 44 static uint32_t ticks_per_us;
<> 150:02e0a0aed4ec 45 static uint32_t tick_win;
<> 150:02e0a0aed4ec 46 static volatile uint64_t current_cnt; // Hold the current ticks
<> 150:02e0a0aed4ec 47 static volatile uint64_t event_cnt; // Holds the value of the next event
<> 150:02e0a0aed4ec 48
<> 150:02e0a0aed4ec 49 #define MAX_TICK_VAL ((uint64_t)0xFFFFFFFF * ticks_per_us)
<> 150:02e0a0aed4ec 50
<> 150:02e0a0aed4ec 51 //******************************************************************************
<> 150:02e0a0aed4ec 52 static inline void inc_current_cnt(uint32_t inc)
<> 150:02e0a0aed4ec 53 {
<> 150:02e0a0aed4ec 54 // Overflow the ticker when the us ticker overflows
<> 150:02e0a0aed4ec 55 current_cnt += inc;
<> 150:02e0a0aed4ec 56 if (current_cnt > MAX_TICK_VAL) {
<> 150:02e0a0aed4ec 57 current_cnt -= (MAX_TICK_VAL + 1);
<> 150:02e0a0aed4ec 58 }
<> 150:02e0a0aed4ec 59 }
<> 150:02e0a0aed4ec 60
<> 150:02e0a0aed4ec 61 //******************************************************************************
<> 150:02e0a0aed4ec 62 static inline int event_passed(uint64_t current, uint64_t event)
<> 150:02e0a0aed4ec 63 {
<> 150:02e0a0aed4ec 64 // Determine if the event has already happened.
<> 150:02e0a0aed4ec 65 // If the event is behind the current ticker, within a window,
<> 150:02e0a0aed4ec 66 // then the event has already happened.
<> 150:02e0a0aed4ec 67 if (((current < tick_win) && ((event < current) ||
<> 150:02e0a0aed4ec 68 (event > (MAX_TICK_VAL - (tick_win - current))))) ||
<> 150:02e0a0aed4ec 69 ((event < current) && (event > (current - tick_win)))) {
<> 150:02e0a0aed4ec 70 return 1;
<> 150:02e0a0aed4ec 71 }
<> 150:02e0a0aed4ec 72
<> 150:02e0a0aed4ec 73 return 0;
<> 150:02e0a0aed4ec 74 }
<> 150:02e0a0aed4ec 75
<> 150:02e0a0aed4ec 76 //******************************************************************************
<> 150:02e0a0aed4ec 77 static inline uint64_t event_diff(uint64_t current, uint64_t event)
<> 150:02e0a0aed4ec 78 {
<> 150:02e0a0aed4ec 79 // Check to see if the ticker will overflow before the event
<> 150:02e0a0aed4ec 80 if(current <= event) {
<> 150:02e0a0aed4ec 81 return (event - current);
<> 150:02e0a0aed4ec 82 }
<> 150:02e0a0aed4ec 83
<> 150:02e0a0aed4ec 84 return ((MAX_TICK_VAL - current) + event);
<> 150:02e0a0aed4ec 85 }
<> 150:02e0a0aed4ec 86
<> 150:02e0a0aed4ec 87 //******************************************************************************
<> 150:02e0a0aed4ec 88 static void tmr_handler(void)
<> 150:02e0a0aed4ec 89 {
<> 150:02e0a0aed4ec 90 uint32_t cmp = TMR32_GetCompare(US_TIMER);
<> 150:02e0a0aed4ec 91 TMR32_SetCompare(US_TIMER, 0xFFFFFFFF); // reset to max value to prevent further interrupts
<> 150:02e0a0aed4ec 92 TMR32_ClearFlag(US_TIMER);
<> 150:02e0a0aed4ec 93 NVIC_ClearPendingIRQ(US_TIMER_IRQn);
<> 150:02e0a0aed4ec 94
<> 150:02e0a0aed4ec 95 inc_current_cnt(cmp);
<> 150:02e0a0aed4ec 96
<> 150:02e0a0aed4ec 97 if (event_passed(current_cnt + TMR32_GetCount(US_TIMER), event_cnt)) {
<> 150:02e0a0aed4ec 98 // the timestamp has expired
<> 150:02e0a0aed4ec 99 event_cnt = 0xFFFFFFFFFFFFFFFFULL; // reset to max value
<> 150:02e0a0aed4ec 100 us_ticker_irq_handler();
<> 150:02e0a0aed4ec 101 } else {
<> 150:02e0a0aed4ec 102 uint64_t diff = event_diff(current_cnt, event_cnt);
<> 150:02e0a0aed4ec 103 if (diff < (uint64_t)0xFFFFFFFF) {
<> 150:02e0a0aed4ec 104 // the event occurs before the next overflow
<> 150:02e0a0aed4ec 105 TMR32_SetCompare(US_TIMER, diff);
<> 150:02e0a0aed4ec 106
<> 150:02e0a0aed4ec 107 // Since the timer keeps counting after the terminal value is reached, it is possible that the new
<> 150:02e0a0aed4ec 108 // terminal value is in the past.
<> 150:02e0a0aed4ec 109 if (TMR32_GetCompare(US_TIMER) < TMR32_GetCount(US_TIMER)) {
<> 150:02e0a0aed4ec 110 // the timestamp has expired
<> 150:02e0a0aed4ec 111 TMR32_SetCompare(US_TIMER, 0xFFFFFFFF); // reset to max value to prevent further interrupts
<> 150:02e0a0aed4ec 112 TMR32_ClearFlag(US_TIMER);
<> 150:02e0a0aed4ec 113 NVIC_ClearPendingIRQ(US_TIMER_IRQn);
<> 150:02e0a0aed4ec 114 event_cnt = 0xFFFFFFFFFFFFFFFFULL; // reset to max value
<> 150:02e0a0aed4ec 115 us_ticker_irq_handler();
<> 150:02e0a0aed4ec 116 }
<> 150:02e0a0aed4ec 117 }
<> 150:02e0a0aed4ec 118 }
<> 150:02e0a0aed4ec 119 }
<> 150:02e0a0aed4ec 120
<> 150:02e0a0aed4ec 121 //******************************************************************************
<> 150:02e0a0aed4ec 122 void us_ticker_init(void)
<> 150:02e0a0aed4ec 123 {
<> 150:02e0a0aed4ec 124 if (us_ticker_inited) {
<> 150:02e0a0aed4ec 125 return;
<> 150:02e0a0aed4ec 126 }
<> 150:02e0a0aed4ec 127
<> 150:02e0a0aed4ec 128 us_ticker_inited = 1;
<> 150:02e0a0aed4ec 129 current_cnt = 0;
<> 150:02e0a0aed4ec 130 event_cnt = 0xFFFFFFFFFFFFFFFFULL; // reset to max value
<> 150:02e0a0aed4ec 131 ticks_per_us = SystemCoreClock / 1000000;
<> 150:02e0a0aed4ec 132 tick_win = SystemCoreClock / 100; // Set the tick window to 10ms
<> 150:02e0a0aed4ec 133
<> 150:02e0a0aed4ec 134 int retval = TMR_Init(US_TIMER, TMR_PRESCALE_DIV_2_0, NULL);
<> 150:02e0a0aed4ec 135 MBED_ASSERT(retval == E_NO_ERROR);
<> 150:02e0a0aed4ec 136
<> 150:02e0a0aed4ec 137 tmr32_cfg_t cfg;
<> 150:02e0a0aed4ec 138 cfg.mode = TMR32_MODE_CONTINUOUS;
<> 150:02e0a0aed4ec 139 cfg.polarity = TMR_POLARITY_UNUSED;
<> 150:02e0a0aed4ec 140 cfg.compareCount = 0xFFFFFFFF;
<> 150:02e0a0aed4ec 141 TMR32_Config(US_TIMER, &cfg);
<> 150:02e0a0aed4ec 142
<> 150:02e0a0aed4ec 143 NVIC_SetVector(US_TIMER_IRQn, (uint32_t)tmr_handler);
<> 150:02e0a0aed4ec 144 NVIC_EnableIRQ(US_TIMER_IRQn);
<> 150:02e0a0aed4ec 145 TMR32_EnableINT(US_TIMER);
<> 150:02e0a0aed4ec 146
<> 150:02e0a0aed4ec 147 TMR32_Start(US_TIMER);
<> 150:02e0a0aed4ec 148 }
<> 150:02e0a0aed4ec 149
<> 150:02e0a0aed4ec 150 //******************************************************************************
<> 150:02e0a0aed4ec 151 void us_ticker_deinit(void)
<> 150:02e0a0aed4ec 152 {
<> 150:02e0a0aed4ec 153 TMR32_Stop(US_TIMER);
<> 150:02e0a0aed4ec 154 TMR32_DisableINT(US_TIMER);
<> 150:02e0a0aed4ec 155 TMR32_ClearFlag(US_TIMER);
<> 150:02e0a0aed4ec 156 us_ticker_inited = 0;
<> 150:02e0a0aed4ec 157 }
<> 150:02e0a0aed4ec 158
<> 150:02e0a0aed4ec 159 //******************************************************************************
<> 150:02e0a0aed4ec 160 uint32_t us_ticker_read(void)
<> 150:02e0a0aed4ec 161 {
<> 150:02e0a0aed4ec 162 uint64_t current_cnt1, current_cnt2;
<> 150:02e0a0aed4ec 163 uint32_t cmp, cnt;
<> 150:02e0a0aed4ec 164 uint32_t flag1, flag2;
<> 150:02e0a0aed4ec 165
<> 150:02e0a0aed4ec 166 if (!us_ticker_inited) {
<> 150:02e0a0aed4ec 167 us_ticker_init();
<> 150:02e0a0aed4ec 168 }
<> 150:02e0a0aed4ec 169
<> 150:02e0a0aed4ec 170 // Ensure coherency between current_cnt and TMR32_GetCount()
<> 150:02e0a0aed4ec 171 do {
<> 150:02e0a0aed4ec 172 current_cnt1 = current_cnt;
<> 150:02e0a0aed4ec 173 flag1 = TMR32_GetFlag(US_TIMER);
<> 150:02e0a0aed4ec 174 cmp = TMR32_GetCompare(US_TIMER);
<> 150:02e0a0aed4ec 175 cnt = TMR32_GetCount(US_TIMER);
<> 150:02e0a0aed4ec 176 flag2 = TMR32_GetFlag(US_TIMER);
<> 150:02e0a0aed4ec 177 current_cnt2 = current_cnt;
<> 150:02e0a0aed4ec 178 } while ((current_cnt1 != current_cnt2) || (flag1 != flag2));
<> 150:02e0a0aed4ec 179
<> 150:02e0a0aed4ec 180 // Account for an unserviced interrupt
<> 150:02e0a0aed4ec 181 if (flag1) {
<> 150:02e0a0aed4ec 182 current_cnt1 += cmp;
<> 150:02e0a0aed4ec 183 }
<> 150:02e0a0aed4ec 184
<> 150:02e0a0aed4ec 185 current_cnt1 += cnt;
<> 150:02e0a0aed4ec 186
<> 150:02e0a0aed4ec 187 return (current_cnt1 / ticks_per_us);
<> 150:02e0a0aed4ec 188 }
<> 150:02e0a0aed4ec 189
<> 150:02e0a0aed4ec 190 //******************************************************************************
<> 150:02e0a0aed4ec 191 void us_ticker_set_interrupt(timestamp_t timestamp)
<> 150:02e0a0aed4ec 192 {
<> 150:02e0a0aed4ec 193 // Note: interrupts are disabled before this function is called.
<> 150:02e0a0aed4ec 194
<> 150:02e0a0aed4ec 195 TMR32_Stop(US_TIMER);
<> 150:02e0a0aed4ec 196
<> 150:02e0a0aed4ec 197 if (TMR32_GetFlag(US_TIMER)) {
<> 150:02e0a0aed4ec 198 TMR32_ClearFlag(US_TIMER);
<> 150:02e0a0aed4ec 199 NVIC_ClearPendingIRQ(US_TIMER_IRQn);
<> 150:02e0a0aed4ec 200 inc_current_cnt(TMR32_GetCompare(US_TIMER));
<> 150:02e0a0aed4ec 201 }
<> 150:02e0a0aed4ec 202
<> 150:02e0a0aed4ec 203 // add and reset the current count value
<> 150:02e0a0aed4ec 204 inc_current_cnt(TMR32_GetCount(US_TIMER));
<> 150:02e0a0aed4ec 205 TMR32_SetCount(US_TIMER, 0);
<> 150:02e0a0aed4ec 206
<> 150:02e0a0aed4ec 207 // add the number of cycles that the timer is disabled here for
<> 150:02e0a0aed4ec 208 inc_current_cnt(200);
<> 150:02e0a0aed4ec 209
<> 150:02e0a0aed4ec 210 event_cnt = (uint64_t)timestamp * ticks_per_us;
<> 150:02e0a0aed4ec 211
<> 150:02e0a0aed4ec 212 // Check to see if the event has already passed
<> 150:02e0a0aed4ec 213 if (!event_passed(current_cnt, event_cnt)) {
<> 150:02e0a0aed4ec 214 uint64_t diff = event_diff(current_cnt, event_cnt);
<> 150:02e0a0aed4ec 215 if (diff < (uint64_t)0xFFFFFFFF) {
<> 150:02e0a0aed4ec 216 // the event occurs before the next overflow
<> 150:02e0a0aed4ec 217 TMR32_SetCompare(US_TIMER, diff);
<> 150:02e0a0aed4ec 218 } else {
<> 150:02e0a0aed4ec 219 // the event occurs after the next overflow
<> 150:02e0a0aed4ec 220 TMR32_SetCompare(US_TIMER, 0xFFFFFFFF); // set to max
<> 150:02e0a0aed4ec 221 }
<> 150:02e0a0aed4ec 222 } else {
<> 150:02e0a0aed4ec 223 // the requested timestamp occurs in the past
<> 150:02e0a0aed4ec 224 // set the timer up to immediately expire
<> 150:02e0a0aed4ec 225 TMR32_SetCompare(US_TIMER, 1);
<> 150:02e0a0aed4ec 226 }
<> 150:02e0a0aed4ec 227
<> 150:02e0a0aed4ec 228 TMR32_Start(US_TIMER);
<> 150:02e0a0aed4ec 229 }
<> 150:02e0a0aed4ec 230
<> 150:02e0a0aed4ec 231 //******************************************************************************
<> 150:02e0a0aed4ec 232 void us_ticker_disable_interrupt(void)
<> 150:02e0a0aed4ec 233 {
<> 150:02e0a0aed4ec 234 // There are no more events, set timer overflow to the max
<> 150:02e0a0aed4ec 235 TMR32_SetCompare(US_TIMER, 0xFFFFFFFF);
<> 150:02e0a0aed4ec 236 }
<> 150:02e0a0aed4ec 237
<> 150:02e0a0aed4ec 238 //******************************************************************************
<> 150:02e0a0aed4ec 239 void us_ticker_clear_interrupt(void)
<> 150:02e0a0aed4ec 240 {
<> 150:02e0a0aed4ec 241 // cleared in the local handler
<> 150:02e0a0aed4ec 242 }
<> 150:02e0a0aed4ec 243
<> 150:02e0a0aed4ec 244 //******************************************************************************
<> 150:02e0a0aed4ec 245 void us_ticker_set(timestamp_t timestamp)
<> 150:02e0a0aed4ec 246 {
<> 150:02e0a0aed4ec 247 TMR32_Stop(US_TIMER);
<> 150:02e0a0aed4ec 248 current_cnt = (uint64_t)timestamp * ticks_per_us;
<> 150:02e0a0aed4ec 249 TMR32_SetCount(US_TIMER, 0);
<> 150:02e0a0aed4ec 250 TMR32_SetCompare(US_TIMER, 0xFFFFFFFF);
<> 150:02e0a0aed4ec 251 TMR32_Start(US_TIMER);
<> 150:02e0a0aed4ec 252
<> 150:02e0a0aed4ec 253 if (((uint64_t)timestamp * ticks_per_us) >= event_cnt) {
<> 150:02e0a0aed4ec 254 // The next timestamp has elapsed. Trigger the interrupt to handle it.
<> 150:02e0a0aed4ec 255 NVIC_SetPendingIRQ(US_TIMER_IRQn);
<> 150:02e0a0aed4ec 256 }
<> 150:02e0a0aed4ec 257 }