Amit Gandhi / mbed-dev

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Fork of mbed-dev by mbed official

targets/TARGET_Maxim/TARGET_MAX32630/us_ticker.c@175:b96e65c34a4d, 2017-10-02 (annotated)

Committer:
AnnaBridge
Date:
Mon Oct 02 15:33:19 2017 +0100
Revision:
175:b96e65c34a4d
Parent:
166:e614a9f1c9e2 
This updates the lib to the mbed lib v 152

Who changed what in which revision?

UserRevisionLine numberNew contents of line
<> 157:ff67d9f36b67 1 /*******************************************************************************
<> 157:ff67d9f36b67 2 * Copyright (c) 2016 Maxim Integrated Products, Inc., All Rights Reserved.
<> 157:ff67d9f36b67 3 *
<> 157:ff67d9f36b67 4 * Permission is hereby granted, free of charge, to any person obtaining a
<> 157:ff67d9f36b67 5 * copy of this software and associated documentation files (the "Software"),
<> 157:ff67d9f36b67 6 * to deal in the Software without restriction, including without limitation
<> 157:ff67d9f36b67 7 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
<> 157:ff67d9f36b67 8 * and/or sell copies of the Software, and to permit persons to whom the
<> 157:ff67d9f36b67 9 * Software is furnished to do so, subject to the following conditions:
<> 157:ff67d9f36b67 10 *
<> 157:ff67d9f36b67 11 * The above copyright notice and this permission notice shall be included
<> 157:ff67d9f36b67 12 * in all copies or substantial portions of the Software.
<> 157:ff67d9f36b67 13 *
<> 157:ff67d9f36b67 14 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
<> 157:ff67d9f36b67 15 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
<> 157:ff67d9f36b67 16 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
<> 157:ff67d9f36b67 17 * IN NO EVENT SHALL MAXIM INTEGRATED BE LIABLE FOR ANY CLAIM, DAMAGES
<> 157:ff67d9f36b67 18 * OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
<> 157:ff67d9f36b67 19 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
<> 157:ff67d9f36b67 20 * OTHER DEALINGS IN THE SOFTWARE.
<> 157:ff67d9f36b67 21 *
<> 157:ff67d9f36b67 22 * Except as contained in this notice, the name of Maxim Integrated
<> 157:ff67d9f36b67 23 * Products, Inc. shall not be used except as stated in the Maxim Integrated
<> 157:ff67d9f36b67 24 * Products, Inc. Branding Policy.
<> 157:ff67d9f36b67 25 *
<> 157:ff67d9f36b67 26 * The mere transfer of this software does not imply any licenses
<> 157:ff67d9f36b67 27 * of trade secrets, proprietary technology, copyrights, patents,
<> 157:ff67d9f36b67 28 * trademarks, maskwork rights, or any other form of intellectual
<> 157:ff67d9f36b67 29 * property whatsoever. Maxim Integrated Products, Inc. retains all
<> 157:ff67d9f36b67 30 * ownership rights.
<> 157:ff67d9f36b67 31 *******************************************************************************
<> 157:ff67d9f36b67 32 */
<> 157:ff67d9f36b67 33
<> 157:ff67d9f36b67 34 #include <stddef.h>
<> 157:ff67d9f36b67 35 #include "mbed_error.h"
<> 157:ff67d9f36b67 36 #include "us_ticker_api.h"
<> 157:ff67d9f36b67 37 #include "PeripheralNames.h"
<> 157:ff67d9f36b67 38 #include "tmr.h"
<> 157:ff67d9f36b67 39
<> 157:ff67d9f36b67 40 #define US_TIMER MXC_TMR0
<> 157:ff67d9f36b67 41 #define US_TIMER_IRQn TMR0_0_IRQn
<> 157:ff67d9f36b67 42
<> 157:ff67d9f36b67 43 static int us_ticker_inited = 0;
<> 157:ff67d9f36b67 44 static uint32_t ticks_per_us;
<> 157:ff67d9f36b67 45 static uint32_t tick_win;
<> 157:ff67d9f36b67 46 static volatile uint64_t current_cnt; // Hold the current ticks
<> 157:ff67d9f36b67 47 static volatile uint64_t event_cnt; // Holds the value of the next event
<> 157:ff67d9f36b67 48
<> 157:ff67d9f36b67 49 #define MAX_TICK_VAL ((uint64_t)0xFFFFFFFF * ticks_per_us)
<> 157:ff67d9f36b67 50
<> 157:ff67d9f36b67 51 //******************************************************************************
<> 157:ff67d9f36b67 52 static inline void inc_current_cnt(uint32_t inc)
<> 157:ff67d9f36b67 53 {
<> 157:ff67d9f36b67 54 // Overflow the ticker when the us ticker overflows
<> 157:ff67d9f36b67 55 current_cnt += inc;
<> 157:ff67d9f36b67 56 if (current_cnt > MAX_TICK_VAL) {
<> 157:ff67d9f36b67 57 current_cnt -= (MAX_TICK_VAL + 1);
<> 157:ff67d9f36b67 58 }
<> 157:ff67d9f36b67 59 }
<> 157:ff67d9f36b67 60
<> 157:ff67d9f36b67 61 //******************************************************************************
<> 157:ff67d9f36b67 62 static inline int event_passed(uint64_t current, uint64_t event)
<> 157:ff67d9f36b67 63 {
<> 157:ff67d9f36b67 64 // Determine if the event has already happened.
<> 157:ff67d9f36b67 65 // If the event is behind the current ticker, within a window,
<> 157:ff67d9f36b67 66 // then the event has already happened.
<> 157:ff67d9f36b67 67 if (((current < tick_win) && ((event < current) ||
<> 157:ff67d9f36b67 68 (event > (MAX_TICK_VAL - (tick_win - current))))) ||
<> 157:ff67d9f36b67 69 ((event < current) && (event > (current - tick_win)))) {
<> 157:ff67d9f36b67 70 return 1;
<> 157:ff67d9f36b67 71 }
<> 157:ff67d9f36b67 72
<> 157:ff67d9f36b67 73 return 0;
<> 157:ff67d9f36b67 74 }
<> 157:ff67d9f36b67 75
<> 157:ff67d9f36b67 76 //******************************************************************************
<> 157:ff67d9f36b67 77 static inline uint64_t event_diff(uint64_t current, uint64_t event)
<> 157:ff67d9f36b67 78 {
<> 157:ff67d9f36b67 79 // Check to see if the ticker will overflow before the event
<> 157:ff67d9f36b67 80 if(current <= event) {
<> 157:ff67d9f36b67 81 return (event - current);
<> 157:ff67d9f36b67 82 }
<> 157:ff67d9f36b67 83
<> 157:ff67d9f36b67 84 return ((MAX_TICK_VAL - current) + event);
<> 157:ff67d9f36b67 85 }
<> 157:ff67d9f36b67 86
<> 157:ff67d9f36b67 87 //******************************************************************************
<> 157:ff67d9f36b67 88 static void tmr_handler(void)
<> 157:ff67d9f36b67 89 {
<> 157:ff67d9f36b67 90 uint32_t cmp = TMR32_GetCompare(US_TIMER);
<> 157:ff67d9f36b67 91 TMR32_SetCompare(US_TIMER, 0xFFFFFFFF); // reset to max value to prevent further interrupts
<> 157:ff67d9f36b67 92 TMR32_ClearFlag(US_TIMER);
<> 157:ff67d9f36b67 93 NVIC_ClearPendingIRQ(US_TIMER_IRQn);
<> 157:ff67d9f36b67 94
<> 157:ff67d9f36b67 95 inc_current_cnt(cmp);
<> 157:ff67d9f36b67 96
<> 157:ff67d9f36b67 97 if (event_passed(current_cnt + TMR32_GetCount(US_TIMER), event_cnt)) {
<> 157:ff67d9f36b67 98 // the timestamp has expired
<> 157:ff67d9f36b67 99 event_cnt = 0xFFFFFFFFFFFFFFFFULL; // reset to max value
<> 157:ff67d9f36b67 100 us_ticker_irq_handler();
<> 157:ff67d9f36b67 101 } else {
<> 157:ff67d9f36b67 102 uint64_t diff = event_diff(current_cnt, event_cnt);
<> 157:ff67d9f36b67 103 if (diff < (uint64_t)0xFFFFFFFF) {
<> 157:ff67d9f36b67 104 // the event occurs before the next overflow
<> 157:ff67d9f36b67 105 TMR32_SetCompare(US_TIMER, diff);
<> 157:ff67d9f36b67 106
<> 157:ff67d9f36b67 107 // Since the timer keeps counting after the terminal value is reached, it is possible that the new
<> 157:ff67d9f36b67 108 // terminal value is in the past.
<> 157:ff67d9f36b67 109 if (TMR32_GetCompare(US_TIMER) < TMR32_GetCount(US_TIMER)) {
<> 157:ff67d9f36b67 110 // the timestamp has expired
<> 157:ff67d9f36b67 111 TMR32_SetCompare(US_TIMER, 0xFFFFFFFF); // reset to max value to prevent further interrupts
<> 157:ff67d9f36b67 112 TMR32_ClearFlag(US_TIMER);
<> 157:ff67d9f36b67 113 NVIC_ClearPendingIRQ(US_TIMER_IRQn);
<> 157:ff67d9f36b67 114 event_cnt = 0xFFFFFFFFFFFFFFFFULL; // reset to max value
<> 157:ff67d9f36b67 115 us_ticker_irq_handler();
<> 157:ff67d9f36b67 116 }
<> 157:ff67d9f36b67 117 }
<> 157:ff67d9f36b67 118 }
<> 157:ff67d9f36b67 119 }
<> 157:ff67d9f36b67 120
<> 157:ff67d9f36b67 121 //******************************************************************************
<> 157:ff67d9f36b67 122 void us_ticker_init(void)
<> 157:ff67d9f36b67 123 {
<> 157:ff67d9f36b67 124 if (us_ticker_inited) {
<> 157:ff67d9f36b67 125 return;
<> 157:ff67d9f36b67 126 }
<> 157:ff67d9f36b67 127
<> 157:ff67d9f36b67 128 us_ticker_inited = 1;
<> 157:ff67d9f36b67 129 current_cnt = 0;
<> 157:ff67d9f36b67 130 event_cnt = 0xFFFFFFFFFFFFFFFFULL; // reset to max value
<> 157:ff67d9f36b67 131 ticks_per_us = SystemCoreClock / 1000000;
<> 157:ff67d9f36b67 132 tick_win = SystemCoreClock / 100; // Set the tick window to 10ms
<> 157:ff67d9f36b67 133
<> 157:ff67d9f36b67 134 int retval = TMR_Init(US_TIMER, TMR_PRESCALE_DIV_2_0, NULL);
<> 157:ff67d9f36b67 135 MBED_ASSERT(retval == E_NO_ERROR);
<> 157:ff67d9f36b67 136
<> 157:ff67d9f36b67 137 tmr32_cfg_t cfg;
<> 157:ff67d9f36b67 138 cfg.mode = TMR32_MODE_CONTINUOUS;
<> 157:ff67d9f36b67 139 cfg.polarity = TMR_POLARITY_UNUSED;
<> 157:ff67d9f36b67 140 cfg.compareCount = 0xFFFFFFFF;
<> 157:ff67d9f36b67 141 TMR32_Config(US_TIMER, &cfg);
<> 157:ff67d9f36b67 142
AnnaBridge 166:e614a9f1c9e2 143 NVIC_SetVector(US_TIMER_IRQn, (uint32_t)tmr_handler);
<> 157:ff67d9f36b67 144 NVIC_EnableIRQ(US_TIMER_IRQn);
<> 157:ff67d9f36b67 145 TMR32_EnableINT(US_TIMER);
<> 157:ff67d9f36b67 146
<> 157:ff67d9f36b67 147 TMR32_Start(US_TIMER);
<> 157:ff67d9f36b67 148 }
<> 157:ff67d9f36b67 149
<> 157:ff67d9f36b67 150 //******************************************************************************
<> 157:ff67d9f36b67 151 void us_ticker_deinit(void)
<> 157:ff67d9f36b67 152 {
<> 157:ff67d9f36b67 153 TMR32_Stop(US_TIMER);
<> 157:ff67d9f36b67 154 TMR32_DisableINT(US_TIMER);
<> 157:ff67d9f36b67 155 TMR32_ClearFlag(US_TIMER);
<> 157:ff67d9f36b67 156 us_ticker_inited = 0;
<> 157:ff67d9f36b67 157 }
<> 157:ff67d9f36b67 158
<> 157:ff67d9f36b67 159 //******************************************************************************
<> 157:ff67d9f36b67 160 uint32_t us_ticker_read(void)
<> 157:ff67d9f36b67 161 {
<> 157:ff67d9f36b67 162 uint64_t current_cnt1, current_cnt2;
<> 157:ff67d9f36b67 163 uint32_t cmp, cnt;
<> 157:ff67d9f36b67 164 uint32_t flag1, flag2;
<> 157:ff67d9f36b67 165
<> 157:ff67d9f36b67 166 if (!us_ticker_inited) {
<> 157:ff67d9f36b67 167 us_ticker_init();
<> 157:ff67d9f36b67 168 }
<> 157:ff67d9f36b67 169
<> 157:ff67d9f36b67 170 // Ensure coherency between current_cnt and TMR32_GetCount()
<> 157:ff67d9f36b67 171 do {
<> 157:ff67d9f36b67 172 current_cnt1 = current_cnt;
<> 157:ff67d9f36b67 173 flag1 = TMR32_GetFlag(US_TIMER);
<> 157:ff67d9f36b67 174 cmp = TMR32_GetCompare(US_TIMER);
<> 157:ff67d9f36b67 175 cnt = TMR32_GetCount(US_TIMER);
<> 157:ff67d9f36b67 176 flag2 = TMR32_GetFlag(US_TIMER);
<> 157:ff67d9f36b67 177 current_cnt2 = current_cnt;
<> 157:ff67d9f36b67 178 } while ((current_cnt1 != current_cnt2) || (flag1 != flag2));
<> 157:ff67d9f36b67 179
<> 157:ff67d9f36b67 180 // Account for an unserviced interrupt
<> 157:ff67d9f36b67 181 if (flag1) {
<> 157:ff67d9f36b67 182 current_cnt1 += cmp;
<> 157:ff67d9f36b67 183 }
<> 157:ff67d9f36b67 184
<> 157:ff67d9f36b67 185 current_cnt1 += cnt;
<> 157:ff67d9f36b67 186
<> 157:ff67d9f36b67 187 return (current_cnt1 / ticks_per_us);
<> 157:ff67d9f36b67 188 }
<> 157:ff67d9f36b67 189
<> 157:ff67d9f36b67 190 //******************************************************************************
<> 157:ff67d9f36b67 191 void us_ticker_set_interrupt(timestamp_t timestamp)
<> 157:ff67d9f36b67 192 {
<> 157:ff67d9f36b67 193 // Note: interrupts are disabled before this function is called.
<> 157:ff67d9f36b67 194
<> 157:ff67d9f36b67 195 TMR32_Stop(US_TIMER);
<> 157:ff67d9f36b67 196
<> 157:ff67d9f36b67 197 if (TMR32_GetFlag(US_TIMER)) {
<> 157:ff67d9f36b67 198 TMR32_ClearFlag(US_TIMER);
<> 157:ff67d9f36b67 199 NVIC_ClearPendingIRQ(US_TIMER_IRQn);
<> 157:ff67d9f36b67 200 inc_current_cnt(TMR32_GetCompare(US_TIMER));
<> 157:ff67d9f36b67 201 }
<> 157:ff67d9f36b67 202
<> 157:ff67d9f36b67 203 // add and reset the current count value
<> 157:ff67d9f36b67 204 inc_current_cnt(TMR32_GetCount(US_TIMER));
<> 157:ff67d9f36b67 205 TMR32_SetCount(US_TIMER, 0);
<> 157:ff67d9f36b67 206
<> 157:ff67d9f36b67 207 // add the number of cycles that the timer is disabled here for
<> 157:ff67d9f36b67 208 inc_current_cnt(200);
<> 157:ff67d9f36b67 209
<> 157:ff67d9f36b67 210 event_cnt = (uint64_t)timestamp * ticks_per_us;
<> 157:ff67d9f36b67 211
<> 157:ff67d9f36b67 212 // Check to see if the event has already passed
<> 157:ff67d9f36b67 213 if (!event_passed(current_cnt, event_cnt)) {
<> 157:ff67d9f36b67 214 uint64_t diff = event_diff(current_cnt, event_cnt);
<> 157:ff67d9f36b67 215 if (diff < (uint64_t)0xFFFFFFFF) {
<> 157:ff67d9f36b67 216 // the event occurs before the next overflow
<> 157:ff67d9f36b67 217 TMR32_SetCompare(US_TIMER, diff);
<> 157:ff67d9f36b67 218 } else {
<> 157:ff67d9f36b67 219 // the event occurs after the next overflow
<> 157:ff67d9f36b67 220 TMR32_SetCompare(US_TIMER, 0xFFFFFFFF); // set to max
<> 157:ff67d9f36b67 221 }
<> 157:ff67d9f36b67 222 } else {
<> 157:ff67d9f36b67 223 // the requested timestamp occurs in the past
<> 157:ff67d9f36b67 224 // set the timer up to immediately expire
<> 157:ff67d9f36b67 225 TMR32_SetCompare(US_TIMER, 1);
<> 157:ff67d9f36b67 226 }
<> 157:ff67d9f36b67 227
<> 157:ff67d9f36b67 228 TMR32_Start(US_TIMER);
<> 157:ff67d9f36b67 229 }
<> 157:ff67d9f36b67 230
AnnaBridge 175:b96e65c34a4d 231 void us_ticker_fire_interrupt(void)
AnnaBridge 175:b96e65c34a4d 232 {
AnnaBridge 175:b96e65c34a4d 233 NVIC_SetPendingIRQ(US_TIMER_IRQn);
AnnaBridge 175:b96e65c34a4d 234 }
AnnaBridge 175:b96e65c34a4d 235
<> 157:ff67d9f36b67 236 //******************************************************************************
<> 157:ff67d9f36b67 237 void us_ticker_disable_interrupt(void)
<> 157:ff67d9f36b67 238 {
<> 157:ff67d9f36b67 239 // There are no more events, set timer overflow to the max
<> 157:ff67d9f36b67 240 TMR32_SetCompare(US_TIMER, 0xFFFFFFFF);
<> 157:ff67d9f36b67 241 }
<> 157:ff67d9f36b67 242
<> 157:ff67d9f36b67 243 //******************************************************************************
<> 157:ff67d9f36b67 244 void us_ticker_clear_interrupt(void)
<> 157:ff67d9f36b67 245 {
<> 157:ff67d9f36b67 246 // cleared in the local handler
<> 157:ff67d9f36b67 247 }
<> 157:ff67d9f36b67 248
<> 157:ff67d9f36b67 249 //******************************************************************************
<> 157:ff67d9f36b67 250 void us_ticker_set(timestamp_t timestamp)
<> 157:ff67d9f36b67 251 {
<> 157:ff67d9f36b67 252 TMR32_Stop(US_TIMER);
<> 157:ff67d9f36b67 253 current_cnt = (uint64_t)timestamp * ticks_per_us;
<> 157:ff67d9f36b67 254 TMR32_SetCount(US_TIMER, 0);
<> 157:ff67d9f36b67 255 TMR32_SetCompare(US_TIMER, 0xFFFFFFFF);
<> 157:ff67d9f36b67 256 TMR32_Start(US_TIMER);
<> 157:ff67d9f36b67 257
<> 157:ff67d9f36b67 258 if (((uint64_t)timestamp * ticks_per_us) >= event_cnt) {
<> 157:ff67d9f36b67 259 // The next timestamp has elapsed. Trigger the interrupt to handle it.
<> 157:ff67d9f36b67 260 NVIC_SetPendingIRQ(US_TIMER_IRQn);
<> 157:ff67d9f36b67 261 }
<> 157:ff67d9f36b67 262 }