marcus chiou / mbed-src

mbed library sources

Fork of mbed-src by mbed official

targets/hal/TARGET_Atmel/TARGET_SAM21/us_ticker.c@579:53297373a894, 2015-07-01 (annotated)

Committer:
mbed_official
Date:
Wed Jul 01 09:45:11 2015 +0100
Revision:
579:53297373a894
Synchronized with git revision d5b4d2ab9c47edb4dc5776e7177b0c2263459081



Full URL: https://github.com/mbedmicro/mbed/commit/d5b4d2ab9c47edb4dc5776e7177b0c2263459081/



Initial version of drivers for SAMR21

Who changed what in which revision?

UserRevisionLine numberNew contents of line
mbed_official 579:53297373a894 1 /* mbed Microcontroller Library
mbed_official 579:53297373a894 2 * Copyright (c) 2006-2013 ARM Limited
mbed_official 579:53297373a894 3 *
mbed_official 579:53297373a894 4 * Licensed under the Apache License, Version 2.0 (the "License");
mbed_official 579:53297373a894 5 * you may not use this file except in compliance with the License.
mbed_official 579:53297373a894 6 * You may obtain a copy of the License at
mbed_official 579:53297373a894 7 *
mbed_official 579:53297373a894 8 * http://www.apache.org/licenses/LICENSE-2.0
mbed_official 579:53297373a894 9 *
mbed_official 579:53297373a894 10 * Unless required by applicable law or agreed to in writing, software
mbed_official 579:53297373a894 11 * distributed under the License is distributed on an "AS IS" BASIS,
mbed_official 579:53297373a894 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
mbed_official 579:53297373a894 13 * See the License for the specific language governing permissions and
mbed_official 579:53297373a894 14 * limitations under the License.
mbed_official 579:53297373a894 15 */
mbed_official 579:53297373a894 16 #include <stddef.h>
mbed_official 579:53297373a894 17 #include "us_ticker_api.h"
mbed_official 579:53297373a894 18 #include "cmsis.h"
mbed_official 579:53297373a894 19 #include "mbed_assert.h"
mbed_official 579:53297373a894 20 #include "ins_gclk.h"
mbed_official 579:53297373a894 21 #include "compiler.h"
mbed_official 579:53297373a894 22 #include "system.h"
mbed_official 579:53297373a894 23 #include "tc.h"
mbed_official 579:53297373a894 24 #include "tc_interrupt.h"
mbed_official 579:53297373a894 25
mbed_official 579:53297373a894 26 #define TICKER_COUNTER_uS TC4
mbed_official 579:53297373a894 27 #define TICKER_COUNTER_IRQn TC4_IRQn
mbed_official 579:53297373a894 28 #define TICKER_COUNTER_Handlr TC4_Handler
mbed_official 579:53297373a894 29
mbed_official 579:53297373a894 30 static int us_ticker_inited = 0;
mbed_official 579:53297373a894 31 extern uint8_t g_sys_init;
mbed_official 579:53297373a894 32
mbed_official 579:53297373a894 33 struct tc_module us_ticker_module;
mbed_official 579:53297373a894 34
mbed_official 579:53297373a894 35
mbed_official 579:53297373a894 36 static inline void tc_clear_interrupt(
mbed_official 579:53297373a894 37 struct tc_module *const module,
mbed_official 579:53297373a894 38 const enum tc_callback callback_type)
mbed_official 579:53297373a894 39 {
mbed_official 579:53297373a894 40 /* Sanity check arguments */
mbed_official 579:53297373a894 41 MBED_ASSERT(module);
mbed_official 579:53297373a894 42
mbed_official 579:53297373a894 43 /* Clear interrupt flags */
mbed_official 579:53297373a894 44 if (callback_type == TC_CALLBACK_CC_CHANNEL0) {
mbed_official 579:53297373a894 45 module->hw->COUNT8.INTENCLR.reg = TC_INTFLAG_MC(1);
mbed_official 579:53297373a894 46 } else if (callback_type == TC_CALLBACK_CC_CHANNEL1) {
mbed_official 579:53297373a894 47 module->hw->COUNT8.INTENCLR.reg = TC_INTFLAG_MC(2);
mbed_official 579:53297373a894 48 } else {
mbed_official 579:53297373a894 49 module->hw->COUNT8.INTENCLR.reg = (1 << callback_type);
mbed_official 579:53297373a894 50 }
mbed_official 579:53297373a894 51 }
mbed_official 579:53297373a894 52
mbed_official 579:53297373a894 53 void us_ticker_irq_handler_internal(struct tc_module* us_tc_module)
mbed_official 579:53297373a894 54 {
mbed_official 579:53297373a894 55 uint32_t status_flags;
mbed_official 579:53297373a894 56
mbed_official 579:53297373a894 57 /* Clear TC capture overflow and TC count overflow */
mbed_official 579:53297373a894 58 status_flags = TC_STATUS_CAPTURE_OVERFLOW | TC_STATUS_COUNT_OVERFLOW;
mbed_official 579:53297373a894 59 tc_clear_status(&us_ticker_module, status_flags);
mbed_official 579:53297373a894 60
mbed_official 579:53297373a894 61 us_ticker_irq_handler();
mbed_official 579:53297373a894 62 }
mbed_official 579:53297373a894 63
mbed_official 579:53297373a894 64 void us_ticker_init(void)
mbed_official 579:53297373a894 65 {
mbed_official 579:53297373a894 66 uint32_t cycles_per_us;
mbed_official 579:53297373a894 67 uint32_t prescaler = 0;
mbed_official 579:53297373a894 68 struct tc_config config_tc;
mbed_official 579:53297373a894 69 enum status_code ret_status;
mbed_official 579:53297373a894 70
mbed_official 579:53297373a894 71 if (us_ticker_inited) return;
mbed_official 579:53297373a894 72 us_ticker_inited = 1;
mbed_official 579:53297373a894 73
mbed_official 579:53297373a894 74 if (g_sys_init == 0) {
mbed_official 579:53297373a894 75 system_init();
mbed_official 579:53297373a894 76 g_sys_init = 1;
mbed_official 579:53297373a894 77 }
mbed_official 579:53297373a894 78
mbed_official 579:53297373a894 79 tc_get_config_defaults(&config_tc);
mbed_official 579:53297373a894 80
mbed_official 579:53297373a894 81 cycles_per_us = system_gclk_gen_get_hz(config_tc.clock_source) / 1000000;
mbed_official 579:53297373a894 82 MBED_ASSERT(cycles_per_us > 0);
mbed_official 579:53297373a894 83 /*while((cycles_per_us & 1) == 0 && prescaler <= 10) {
mbed_official 579:53297373a894 84 cycles_per_us = cycles_per_us >> 1;
mbed_official 579:53297373a894 85 prescaler++;
mbed_official 579:53297373a894 86 }*/
mbed_official 579:53297373a894 87 while((cycles_per_us > 1) && (prescaler <= 10)) {
mbed_official 579:53297373a894 88 cycles_per_us = cycles_per_us >> 1;
mbed_official 579:53297373a894 89 prescaler++;
mbed_official 579:53297373a894 90 }
mbed_official 579:53297373a894 91 if (prescaler >= 9) {
mbed_official 579:53297373a894 92 prescaler = 7;
mbed_official 579:53297373a894 93 } else if (prescaler >= 7) {
mbed_official 579:53297373a894 94 prescaler = 6;
mbed_official 579:53297373a894 95 } else if (prescaler >= 5) {
mbed_official 579:53297373a894 96 prescaler = 5;
mbed_official 579:53297373a894 97 }
mbed_official 579:53297373a894 98
mbed_official 579:53297373a894 99 config_tc.clock_prescaler = TC_CTRLA_PRESCALER(prescaler);
mbed_official 579:53297373a894 100 config_tc.counter_size = TC_COUNTER_SIZE_32BIT;
mbed_official 579:53297373a894 101 config_tc.run_in_standby = true;
mbed_official 579:53297373a894 102 config_tc.counter_32_bit.value = 0;
mbed_official 579:53297373a894 103 config_tc.counter_32_bit.compare_capture_channel[TC_COMPARE_CAPTURE_CHANNEL_0] = 0xFFFFFFFF;
mbed_official 579:53297373a894 104
mbed_official 579:53297373a894 105 /* Initialize the timer */
mbed_official 579:53297373a894 106 ret_status = tc_init(&us_ticker_module, TICKER_COUNTER_uS, &config_tc);
mbed_official 579:53297373a894 107 MBED_ASSERT(ret_status == STATUS_OK);
mbed_official 579:53297373a894 108
mbed_official 579:53297373a894 109 /* Register callback function */
mbed_official 579:53297373a894 110 tc_register_callback(&us_ticker_module, (tc_callback_t)us_ticker_irq_handler_internal, TC_CALLBACK_CC_CHANNEL0);
mbed_official 579:53297373a894 111
mbed_official 579:53297373a894 112 /* Enable the timer module */
mbed_official 579:53297373a894 113 tc_enable(&us_ticker_module);
mbed_official 579:53297373a894 114 }
mbed_official 579:53297373a894 115
mbed_official 579:53297373a894 116 uint32_t us_ticker_read()
mbed_official 579:53297373a894 117 {
mbed_official 579:53297373a894 118 if (!us_ticker_inited)
mbed_official 579:53297373a894 119 us_ticker_init();
mbed_official 579:53297373a894 120
mbed_official 579:53297373a894 121 return tc_get_count_value(&us_ticker_module);
mbed_official 579:53297373a894 122 }
mbed_official 579:53297373a894 123
mbed_official 579:53297373a894 124 void us_ticker_set_interrupt(timestamp_t timestamp)
mbed_official 579:53297373a894 125 {
mbed_official 579:53297373a894 126 uint32_t cur_time;
mbed_official 579:53297373a894 127 int32_t delta;
mbed_official 579:53297373a894 128
mbed_official 579:53297373a894 129 cur_time = us_ticker_read();
mbed_official 579:53297373a894 130 delta = (int32_t)((uint32_t)timestamp - cur_time);
mbed_official 579:53297373a894 131 if (delta < 0) {
mbed_official 579:53297373a894 132 /* Event already occurred in past */
mbed_official 579:53297373a894 133 us_ticker_irq_handler();
mbed_official 579:53297373a894 134 return;
mbed_official 579:53297373a894 135 }
mbed_official 579:53297373a894 136
mbed_official 579:53297373a894 137 NVIC_DisableIRQ(TICKER_COUNTER_IRQn);
mbed_official 579:53297373a894 138 NVIC_SetVector(TICKER_COUNTER_IRQn, (uint32_t)TICKER_COUNTER_Handlr);
mbed_official 579:53297373a894 139
mbed_official 579:53297373a894 140 /* Enable the callback */
mbed_official 579:53297373a894 141 tc_enable_callback(&us_ticker_module, TC_CALLBACK_CC_CHANNEL0);
mbed_official 579:53297373a894 142 tc_set_compare_value(&us_ticker_module, TC_COMPARE_CAPTURE_CHANNEL_0, (uint32_t)timestamp);
mbed_official 579:53297373a894 143
mbed_official 579:53297373a894 144 NVIC_EnableIRQ(TICKER_COUNTER_IRQn);
mbed_official 579:53297373a894 145 }
mbed_official 579:53297373a894 146
mbed_official 579:53297373a894 147 void us_ticker_disable_interrupt(void)
mbed_official 579:53297373a894 148 {
mbed_official 579:53297373a894 149 /* Disable the callback */
mbed_official 579:53297373a894 150 tc_disable_callback(&us_ticker_module, TC_CALLBACK_CC_CHANNEL0);
mbed_official 579:53297373a894 151 NVIC_DisableIRQ(TICKER_COUNTER_IRQn);
mbed_official 579:53297373a894 152 }
mbed_official 579:53297373a894 153
mbed_official 579:53297373a894 154 void us_ticker_clear_interrupt(void)
mbed_official 579:53297373a894 155 {
mbed_official 579:53297373a894 156 uint32_t status_flags;
mbed_official 579:53297373a894 157
mbed_official 579:53297373a894 158 /* Clear TC channel 0 match */
mbed_official 579:53297373a894 159 status_flags = TC_STATUS_CHANNEL_0_MATCH;
mbed_official 579:53297373a894 160 tc_clear_status(&us_ticker_module, status_flags);
mbed_official 579:53297373a894 161
mbed_official 579:53297373a894 162 /* Clear the interrupt */
mbed_official 579:53297373a894 163 tc_clear_interrupt(&us_ticker_module, TC_CALLBACK_CC_CHANNEL0);
mbed_official 579:53297373a894 164 NVIC_ClearPendingIRQ(TICKER_COUNTER_IRQn);
mbed_official 579:53297373a894 165 }