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Last commit 20 Feb 2019 by mbed official

targets/hal/TARGET_Maxim/TARGET_MAX32610/us_ticker.c@536:c48d7048ab6e, 2015-05-07 (annotated)

Committer:
mbed_official
Date:
Thu May 07 09:00:08 2015 +0100
Revision:
536:c48d7048ab6e
Parent:
515:7467ef1f4ad8 
Synchronized with git revision a1e04f782bf013aeb4122c3ec408e3b011de60ed



Full URL: https://github.com/mbedmicro/mbed/commit/a1e04f782bf013aeb4122c3ec408e3b011de60ed/



MAX32600MBED,MAXWSNENV  - Add low-power ticker.

Who changed what in which revision?

UserRevisionLine numberNew contents of line
mbed_official 507:d4fc7603a669 1 /*******************************************************************************
mbed_official 507:d4fc7603a669 2 * Copyright (C) 2015 Maxim Integrated Products, Inc., All Rights Reserved.
mbed_official 507:d4fc7603a669 3 *
mbed_official 507:d4fc7603a669 4 * Permission is hereby granted, free of charge, to any person obtaining a
mbed_official 507:d4fc7603a669 5 * copy of this software and associated documentation files (the "Software"),
mbed_official 507:d4fc7603a669 6 * to deal in the Software without restriction, including without limitation
mbed_official 507:d4fc7603a669 7 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
mbed_official 507:d4fc7603a669 8 * and/or sell copies of the Software, and to permit persons to whom the
mbed_official 507:d4fc7603a669 9 * Software is furnished to do so, subject to the following conditions:
mbed_official 507:d4fc7603a669 10 *
mbed_official 507:d4fc7603a669 11 * The above copyright notice and this permission notice shall be included
mbed_official 507:d4fc7603a669 12 * in all copies or substantial portions of the Software.
mbed_official 507:d4fc7603a669 13 *
mbed_official 507:d4fc7603a669 14 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
mbed_official 507:d4fc7603a669 15 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
mbed_official 507:d4fc7603a669 16 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
mbed_official 507:d4fc7603a669 17 * IN NO EVENT SHALL MAXIM INTEGRATED BE LIABLE FOR ANY CLAIM, DAMAGES
mbed_official 507:d4fc7603a669 18 * OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
mbed_official 507:d4fc7603a669 19 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
mbed_official 507:d4fc7603a669 20 * OTHER DEALINGS IN THE SOFTWARE.
mbed_official 507:d4fc7603a669 21 *
mbed_official 507:d4fc7603a669 22 * Except as contained in this notice, the name of Maxim Integrated
mbed_official 507:d4fc7603a669 23 * Products, Inc. shall not be used except as stated in the Maxim Integrated
mbed_official 507:d4fc7603a669 24 * Products, Inc. Branding Policy.
mbed_official 507:d4fc7603a669 25 *
mbed_official 507:d4fc7603a669 26 * The mere transfer of this software does not imply any licenses
mbed_official 507:d4fc7603a669 27 * of trade secrets, proprietary technology, copyrights, patents,
mbed_official 507:d4fc7603a669 28 * trademarks, maskwork rights, or any other form of intellectual
mbed_official 507:d4fc7603a669 29 * property whatsoever. Maxim Integrated Products, Inc. retains all
mbed_official 507:d4fc7603a669 30 * ownership rights.
mbed_official 507:d4fc7603a669 31 *******************************************************************************
mbed_official 507:d4fc7603a669 32 */
mbed_official 536:c48d7048ab6e 33
mbed_official 507:d4fc7603a669 34 #include "mbed_error.h"
mbed_official 507:d4fc7603a669 35 #include "us_ticker_api.h"
mbed_official 507:d4fc7603a669 36 #include "PeripheralNames.h"
mbed_official 507:d4fc7603a669 37 #include "tmr_regs.h"
mbed_official 507:d4fc7603a669 38
mbed_official 507:d4fc7603a669 39 #define US_TIMER MXC_TMR0
mbed_official 507:d4fc7603a669 40 #define US_TIMER_IRQn TMR0_IRQn
mbed_official 507:d4fc7603a669 41
mbed_official 507:d4fc7603a669 42 static int us_ticker_inited = 0;
mbed_official 507:d4fc7603a669 43 static uint32_t ticks_per_us;
mbed_official 507:d4fc7603a669 44 static uint32_t tick_win;
mbed_official 507:d4fc7603a669 45 static volatile uint64_t current_cnt; // Hold the current ticks
mbed_official 507:d4fc7603a669 46 static volatile uint64_t event_cnt; // Holds the value of the next event
mbed_official 507:d4fc7603a669 47
mbed_official 507:d4fc7603a669 48 #define ticks_to_us(ticks) ((ticks) / ticks_per_us);
mbed_official 507:d4fc7603a669 49 #define MAX_TICK_VAL ((uint64_t)0xFFFFFFFF * ticks_per_us)
mbed_official 507:d4fc7603a669 50
mbed_official 507:d4fc7603a669 51 //******************************************************************************
mbed_official 507:d4fc7603a669 52 static inline void inc_current_cnt(uint32_t inc) {
mbed_official 507:d4fc7603a669 53
mbed_official 507:d4fc7603a669 54 // Overflow the ticker when the us ticker overflows
mbed_official 507:d4fc7603a669 55 current_cnt += inc;
mbed_official 536:c48d7048ab6e 56 if (current_cnt > MAX_TICK_VAL) {
mbed_official 507:d4fc7603a669 57 current_cnt -= (MAX_TICK_VAL + 1);
mbed_official 507:d4fc7603a669 58 }
mbed_official 507:d4fc7603a669 59 }
mbed_official 507:d4fc7603a669 60
mbed_official 507:d4fc7603a669 61 //******************************************************************************
mbed_official 507:d4fc7603a669 62 static inline int event_passed(uint64_t current, uint64_t event) {
mbed_official 507:d4fc7603a669 63
mbed_official 507:d4fc7603a669 64 // Determine if the event has already happened.
mbed_official 507:d4fc7603a669 65 // If the event is behind the current ticker, within a window,
mbed_official 507:d4fc7603a669 66 // then the event has already happened.
mbed_official 536:c48d7048ab6e 67 if (((current < tick_win) && ((event < current) ||
mbed_official 507:d4fc7603a669 68 (event > (MAX_TICK_VAL - (tick_win - current))))) ||
mbed_official 507:d4fc7603a669 69 ((event < current) && (event > (current - tick_win)))) {
mbed_official 507:d4fc7603a669 70 return 1;
mbed_official 507:d4fc7603a669 71 }
mbed_official 507:d4fc7603a669 72
mbed_official 507:d4fc7603a669 73 return 0;
mbed_official 507:d4fc7603a669 74 }
mbed_official 507:d4fc7603a669 75
mbed_official 507:d4fc7603a669 76 //******************************************************************************
mbed_official 507:d4fc7603a669 77 static inline uint64_t event_diff(uint64_t current, uint64_t event) {
mbed_official 507:d4fc7603a669 78
mbed_official 507:d4fc7603a669 79 // Check to see if the ticker will overflow before the event
mbed_official 507:d4fc7603a669 80 if(current <= event) {
mbed_official 507:d4fc7603a669 81 return (event - current);
mbed_official 507:d4fc7603a669 82 }
mbed_official 507:d4fc7603a669 83
mbed_official 507:d4fc7603a669 84 return ((MAX_TICK_VAL - current) + event);
mbed_official 507:d4fc7603a669 85 }
mbed_official 507:d4fc7603a669 86
mbed_official 507:d4fc7603a669 87 //******************************************************************************
mbed_official 507:d4fc7603a669 88 static void tmr_handler(void)
mbed_official 507:d4fc7603a669 89 {
mbed_official 507:d4fc7603a669 90 uint32_t term_cnt32 = US_TIMER->term_cnt32;
mbed_official 507:d4fc7603a669 91 US_TIMER->term_cnt32 = 0xFFFFFFFF; // reset to max value to prevent further interrupts
mbed_official 507:d4fc7603a669 92 US_TIMER->intfl = (MXC_F_TMR_INTFL_TIMER0 | MXC_F_TMR_INTFL_TIMER1); // clear interrupt
mbed_official 507:d4fc7603a669 93 NVIC_ClearPendingIRQ(US_TIMER_IRQn);
mbed_official 507:d4fc7603a669 94
mbed_official 507:d4fc7603a669 95 inc_current_cnt(term_cnt32);
mbed_official 507:d4fc7603a669 96
mbed_official 507:d4fc7603a669 97 if (event_passed(current_cnt + US_TIMER->count32, event_cnt )) {
mbed_official 507:d4fc7603a669 98 // the timestamp has expired
mbed_official 515:7467ef1f4ad8 99 event_cnt = 0xFFFFFFFFFFFFFFFFULL; // reset to max value
mbed_official 507:d4fc7603a669 100 us_ticker_irq_handler();
mbed_official 507:d4fc7603a669 101 } else {
mbed_official 507:d4fc7603a669 102
mbed_official 507:d4fc7603a669 103 uint64_t diff = event_diff(current_cnt, event_cnt);
mbed_official 507:d4fc7603a669 104 if (diff < (uint64_t)0xFFFFFFFF) {
mbed_official 507:d4fc7603a669 105 // the event occurs before the next overflow
mbed_official 507:d4fc7603a669 106 US_TIMER->term_cnt32 = diff;
mbed_official 507:d4fc7603a669 107
mbed_official 507:d4fc7603a669 108 // Since the timer keeps counting after the terminal value is reached, it is possible that the new
mbed_official 507:d4fc7603a669 109 // terminal value is in the past.
mbed_official 507:d4fc7603a669 110 if (US_TIMER->term_cnt32 < US_TIMER->count32) {
mbed_official 507:d4fc7603a669 111 // the timestamp has expired
mbed_official 507:d4fc7603a669 112 US_TIMER->term_cnt32 = 0xFFFFFFFF; // reset to max value to prevent further interrupts
mbed_official 507:d4fc7603a669 113 US_TIMER->intfl = (MXC_F_TMR_INTFL_TIMER0 | MXC_F_TMR_INTFL_TIMER1); // clear interrupt
mbed_official 507:d4fc7603a669 114 NVIC_ClearPendingIRQ(US_TIMER_IRQn);
mbed_official 515:7467ef1f4ad8 115 event_cnt = 0xFFFFFFFFFFFFFFFFULL; // reset to max value
mbed_official 507:d4fc7603a669 116 us_ticker_irq_handler();
mbed_official 507:d4fc7603a669 117 }
mbed_official 507:d4fc7603a669 118 }
mbed_official 507:d4fc7603a669 119 }
mbed_official 507:d4fc7603a669 120 }
mbed_official 507:d4fc7603a669 121
mbed_official 507:d4fc7603a669 122 //******************************************************************************
mbed_official 507:d4fc7603a669 123 void us_ticker_init(void)
mbed_official 507:d4fc7603a669 124 {
mbed_official 507:d4fc7603a669 125 if (us_ticker_inited)
mbed_official 507:d4fc7603a669 126 return;
mbed_official 507:d4fc7603a669 127 us_ticker_inited = 1;
mbed_official 507:d4fc7603a669 128
mbed_official 507:d4fc7603a669 129 current_cnt = 0;
mbed_official 515:7467ef1f4ad8 130 event_cnt = 0xFFFFFFFFFFFFFFFFULL; // reset to max value
mbed_official 507:d4fc7603a669 131
mbed_official 507:d4fc7603a669 132 if (SystemCoreClock <= 1000000) {
mbed_official 507:d4fc7603a669 133 error("us_ticker cannot operate at this SystemCoreClock");
mbed_official 507:d4fc7603a669 134 return;
mbed_official 507:d4fc7603a669 135 }
mbed_official 507:d4fc7603a669 136
mbed_official 507:d4fc7603a669 137 // Configure timer for 32-bit continuous mode with /1 prescaler
mbed_official 507:d4fc7603a669 138 US_TIMER->ctrl = MXC_E_TMR_MODE_CONTINUOUS << MXC_F_TMR_CTRL_MODE_POS | (0 << MXC_F_TMR_CTRL_PRESCALE_POS);
mbed_official 507:d4fc7603a669 139 ticks_per_us = SystemCoreClock / 1000000;
mbed_official 507:d4fc7603a669 140
mbed_official 507:d4fc7603a669 141 // Set the tick window to 10ms
mbed_official 507:d4fc7603a669 142 tick_win = SystemCoreClock/100;
mbed_official 507:d4fc7603a669 143
mbed_official 507:d4fc7603a669 144 // Set timer overflow to the max
mbed_official 507:d4fc7603a669 145 US_TIMER->term_cnt32 = 0xFFFFFFFF;
mbed_official 507:d4fc7603a669 146 US_TIMER->pwm_cap32 = 0xFFFFFFFF;
mbed_official 507:d4fc7603a669 147 US_TIMER->count32 = 0;
mbed_official 507:d4fc7603a669 148
mbed_official 507:d4fc7603a669 149 US_TIMER->intfl = (MXC_F_TMR_INTFL_TIMER0 | MXC_F_TMR_INTFL_TIMER1); // clear pending interrupts
mbed_official 507:d4fc7603a669 150
mbed_official 507:d4fc7603a669 151 NVIC_SetVector(US_TIMER_IRQn, (uint32_t)tmr_handler);
mbed_official 507:d4fc7603a669 152 NVIC_EnableIRQ(US_TIMER_IRQn);
mbed_official 507:d4fc7603a669 153
mbed_official 507:d4fc7603a669 154 US_TIMER->inten |= MXC_F_TMR_INTEN_TIMER0; // enable interrupts
mbed_official 507:d4fc7603a669 155 US_TIMER->ctrl |= MXC_F_TMR_CTRL_ENABLE0; // enable timer
mbed_official 507:d4fc7603a669 156 }
mbed_official 507:d4fc7603a669 157
mbed_official 507:d4fc7603a669 158 //******************************************************************************
mbed_official 507:d4fc7603a669 159 void us_ticker_deinit(void)
mbed_official 507:d4fc7603a669 160 {
mbed_official 507:d4fc7603a669 161 US_TIMER->ctrl = 0; // disable timer
mbed_official 507:d4fc7603a669 162 US_TIMER->inten = 0; // disable interrupts
mbed_official 507:d4fc7603a669 163 US_TIMER->intfl = (MXC_F_TMR_INTFL_TIMER0 | MXC_F_TMR_INTFL_TIMER1); // clear interrupts
mbed_official 507:d4fc7603a669 164 us_ticker_inited = 0;
mbed_official 507:d4fc7603a669 165 }
mbed_official 507:d4fc7603a669 166
mbed_official 507:d4fc7603a669 167 //******************************************************************************
mbed_official 507:d4fc7603a669 168 uint32_t us_ticker_read(void)
mbed_official 507:d4fc7603a669 169 {
mbed_official 507:d4fc7603a669 170 uint64_t current_cnt1, current_cnt2;
mbed_official 507:d4fc7603a669 171 uint32_t term_cnt, tmr_cnt;
mbed_official 536:c48d7048ab6e 172 uint32_t intfl1, intfl2;
mbed_official 507:d4fc7603a669 173
mbed_official 507:d4fc7603a669 174 if (!us_ticker_inited)
mbed_official 507:d4fc7603a669 175 us_ticker_init();
mbed_official 507:d4fc7603a669 176
mbed_official 507:d4fc7603a669 177 // Ensure coherency between current_cnt and US_TIMER->count32
mbed_official 507:d4fc7603a669 178 do {
mbed_official 507:d4fc7603a669 179 current_cnt1 = current_cnt;
mbed_official 507:d4fc7603a669 180 intfl1 = US_TIMER->intfl;
mbed_official 507:d4fc7603a669 181 term_cnt = US_TIMER->term_cnt32;
mbed_official 507:d4fc7603a669 182 tmr_cnt = US_TIMER->count32;
mbed_official 507:d4fc7603a669 183 intfl2 = US_TIMER->intfl;
mbed_official 507:d4fc7603a669 184 current_cnt2 = current_cnt;
mbed_official 507:d4fc7603a669 185 } while ((current_cnt1 != current_cnt2) || (intfl1 != intfl2));
mbed_official 507:d4fc7603a669 186
mbed_official 536:c48d7048ab6e 187 // Account for an unserviced interrupt
mbed_official 507:d4fc7603a669 188 if (intfl1) {
mbed_official 507:d4fc7603a669 189 current_cnt1 += term_cnt;
mbed_official 507:d4fc7603a669 190 }
mbed_official 507:d4fc7603a669 191
mbed_official 507:d4fc7603a669 192 current_cnt1 += tmr_cnt;
mbed_official 507:d4fc7603a669 193
mbed_official 507:d4fc7603a669 194 return (current_cnt1 / ticks_per_us);
mbed_official 507:d4fc7603a669 195 }
mbed_official 507:d4fc7603a669 196
mbed_official 507:d4fc7603a669 197 //******************************************************************************
mbed_official 507:d4fc7603a669 198 void us_ticker_set_interrupt(timestamp_t timestamp)
mbed_official 507:d4fc7603a669 199 {
mbed_official 507:d4fc7603a669 200 // Note: interrupts are disabled before this function is called.
mbed_official 536:c48d7048ab6e 201
mbed_official 507:d4fc7603a669 202 US_TIMER->ctrl &= ~MXC_F_TMR_CTRL_ENABLE0; // disable timer
mbed_official 507:d4fc7603a669 203
mbed_official 507:d4fc7603a669 204 if (US_TIMER->intfl) {
mbed_official 507:d4fc7603a669 205 US_TIMER->intfl = (MXC_F_TMR_INTFL_TIMER0 | MXC_F_TMR_INTFL_TIMER1); // clear interrupt
mbed_official 507:d4fc7603a669 206 NVIC_ClearPendingIRQ(US_TIMER_IRQn);
mbed_official 507:d4fc7603a669 207 inc_current_cnt(US_TIMER->term_cnt32);
mbed_official 507:d4fc7603a669 208 }
mbed_official 507:d4fc7603a669 209
mbed_official 507:d4fc7603a669 210 // add and reset the current count value
mbed_official 507:d4fc7603a669 211 inc_current_cnt(US_TIMER->count32);
mbed_official 507:d4fc7603a669 212 US_TIMER->count32 = 0;
mbed_official 507:d4fc7603a669 213
mbed_official 507:d4fc7603a669 214 // add the number of cycles that the timer is disabled here for
mbed_official 507:d4fc7603a669 215 inc_current_cnt(200);
mbed_official 507:d4fc7603a669 216
mbed_official 507:d4fc7603a669 217 event_cnt = (uint64_t)timestamp * ticks_per_us;
mbed_official 507:d4fc7603a669 218
mbed_official 507:d4fc7603a669 219 // Check to see if the event has already passed
mbed_official 507:d4fc7603a669 220 if (!event_passed(current_cnt, event_cnt)) {
mbed_official 507:d4fc7603a669 221 uint64_t diff = event_diff(current_cnt, event_cnt);
mbed_official 507:d4fc7603a669 222 if (diff < (uint64_t)0xFFFFFFFF) {
mbed_official 507:d4fc7603a669 223 // the event occurs before the next overflow
mbed_official 507:d4fc7603a669 224 US_TIMER->term_cnt32 = diff;
mbed_official 507:d4fc7603a669 225 } else {
mbed_official 507:d4fc7603a669 226 // the event occurs after the next overflow
mbed_official 507:d4fc7603a669 227 US_TIMER->term_cnt32 = 0xFFFFFFFF; // set to max
mbed_official 507:d4fc7603a669 228 }
mbed_official 507:d4fc7603a669 229 } else {
mbed_official 507:d4fc7603a669 230 // the requested timestamp occurs in the past
mbed_official 507:d4fc7603a669 231 // set the timer up to immediately expire
mbed_official 507:d4fc7603a669 232 US_TIMER->term_cnt32 = 1;
mbed_official 507:d4fc7603a669 233 }
mbed_official 507:d4fc7603a669 234 US_TIMER->ctrl |= MXC_F_TMR_CTRL_ENABLE0; // enable timer
mbed_official 507:d4fc7603a669 235 }
mbed_official 507:d4fc7603a669 236
mbed_official 507:d4fc7603a669 237 //******************************************************************************
mbed_official 507:d4fc7603a669 238 void us_ticker_disable_interrupt(void)
mbed_official 507:d4fc7603a669 239 {
mbed_official 507:d4fc7603a669 240 // There are no more events, set timer overflow to the max
mbed_official 507:d4fc7603a669 241 US_TIMER->term_cnt32 = 0xFFFFFFFF;
mbed_official 507:d4fc7603a669 242 }
mbed_official 507:d4fc7603a669 243
mbed_official 507:d4fc7603a669 244 //******************************************************************************
mbed_official 507:d4fc7603a669 245 void us_ticker_clear_interrupt(void)
mbed_official 507:d4fc7603a669 246 {
mbed_official 507:d4fc7603a669 247 // cleared in the local handler
mbed_official 507:d4fc7603a669 248 }
mbed_official 507:d4fc7603a669 249
mbed_official 507:d4fc7603a669 250 //******************************************************************************
mbed_official 507:d4fc7603a669 251 void us_ticker_set(timestamp_t timestamp)
mbed_official 507:d4fc7603a669 252 {
mbed_official 507:d4fc7603a669 253 US_TIMER->ctrl &= ~MXC_F_TMR_CTRL_ENABLE0; // disable timer
mbed_official 507:d4fc7603a669 254 current_cnt = (uint64_t)timestamp * ticks_per_us;
mbed_official 507:d4fc7603a669 255 US_TIMER->count32 = 0;
mbed_official 507:d4fc7603a669 256 US_TIMER->term_cnt32 = 0xFFFFFFFF;
mbed_official 507:d4fc7603a669 257 US_TIMER->ctrl |= MXC_F_TMR_CTRL_ENABLE0; // enable timer
mbed_official 507:d4fc7603a669 258
mbed_official 507:d4fc7603a669 259 if (((uint64_t)timestamp * ticks_per_us) >= event_cnt) {
mbed_official 507:d4fc7603a669 260 // The next timestamp has elapsed. Trigger the interrupt to handle it.
mbed_official 507:d4fc7603a669 261 NVIC_SetPendingIRQ(US_TIMER_IRQn);
mbed_official 507:d4fc7603a669 262 }
mbed_official 507:d4fc7603a669 263 }