Johannes Stratmann / mbed-dev

added prescaler for 16 bit pwm in LPC1347 target

Fork of mbed-dev by mbed official

common/mbed_ticker_api.c@147:ba84b7dc41a7, 2016-09-10 (annotated)

Committer:
JojoS
Date:
Sat Sep 10 15:32:04 2016 +0000
Revision:
147:ba84b7dc41a7
Parent:
144:ef7eb2e8f9f7 
added prescaler for 16 bit timers (solution as in LPC11xx), default prescaler 31 for max 28 ms period time

Who changed what in which revision?

UserRevisionLine numberNew contents of line
<> 144:ef7eb2e8f9f7 1 /* mbed Microcontroller Library
<> 144:ef7eb2e8f9f7 2 * Copyright (c) 2015 ARM Limited
<> 144:ef7eb2e8f9f7 3 *
<> 144:ef7eb2e8f9f7 4 * Licensed under the Apache License, Version 2.0 (the "License");
<> 144:ef7eb2e8f9f7 5 * you may not use this file except in compliance with the License.
<> 144:ef7eb2e8f9f7 6 * You may obtain a copy of the License at
<> 144:ef7eb2e8f9f7 7 *
<> 144:ef7eb2e8f9f7 8 * http://www.apache.org/licenses/LICENSE-2.0
<> 144:ef7eb2e8f9f7 9 *
<> 144:ef7eb2e8f9f7 10 * Unless required by applicable law or agreed to in writing, software
<> 144:ef7eb2e8f9f7 11 * distributed under the License is distributed on an "AS IS" BASIS,
<> 144:ef7eb2e8f9f7 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
<> 144:ef7eb2e8f9f7 13 * See the License for the specific language governing permissions and
<> 144:ef7eb2e8f9f7 14 * limitations under the License.
<> 144:ef7eb2e8f9f7 15 */
<> 144:ef7eb2e8f9f7 16 #include <stddef.h>
<> 144:ef7eb2e8f9f7 17 #include "ticker_api.h"
<> 144:ef7eb2e8f9f7 18 #include "critical.h"
<> 144:ef7eb2e8f9f7 19
<> 144:ef7eb2e8f9f7 20 void ticker_set_handler(const ticker_data_t *const data, ticker_event_handler handler) {
<> 144:ef7eb2e8f9f7 21 data->interface->init();
<> 144:ef7eb2e8f9f7 22
<> 144:ef7eb2e8f9f7 23 data->queue->event_handler = handler;
<> 144:ef7eb2e8f9f7 24 }
<> 144:ef7eb2e8f9f7 25
<> 144:ef7eb2e8f9f7 26 void ticker_irq_handler(const ticker_data_t *const data) {
<> 144:ef7eb2e8f9f7 27 data->interface->clear_interrupt();
<> 144:ef7eb2e8f9f7 28
<> 144:ef7eb2e8f9f7 29 /* Go through all the pending TimerEvents */
<> 144:ef7eb2e8f9f7 30 while (1) {
<> 144:ef7eb2e8f9f7 31 if (data->queue->head == NULL) {
<> 144:ef7eb2e8f9f7 32 // There are no more TimerEvents left, so disable matches.
<> 144:ef7eb2e8f9f7 33 data->interface->disable_interrupt();
<> 144:ef7eb2e8f9f7 34 return;
<> 144:ef7eb2e8f9f7 35 }
<> 144:ef7eb2e8f9f7 36
<> 144:ef7eb2e8f9f7 37 if ((int)(data->queue->head->timestamp - data->interface->read()) <= 0) {
<> 144:ef7eb2e8f9f7 38 // This event was in the past:
<> 144:ef7eb2e8f9f7 39 // point to the following one and execute its handler
<> 144:ef7eb2e8f9f7 40 ticker_event_t *p = data->queue->head;
<> 144:ef7eb2e8f9f7 41 data->queue->head = data->queue->head->next;
<> 144:ef7eb2e8f9f7 42 if (data->queue->event_handler != NULL) {
<> 144:ef7eb2e8f9f7 43 (*data->queue->event_handler)(p->id); // NOTE: the handler can set new events
<> 144:ef7eb2e8f9f7 44 }
<> 144:ef7eb2e8f9f7 45 /* Note: We continue back to examining the head because calling the
<> 144:ef7eb2e8f9f7 46 * event handler may have altered the chain of pending events. */
<> 144:ef7eb2e8f9f7 47 } else {
<> 144:ef7eb2e8f9f7 48 // This event and the following ones in the list are in the future:
<> 144:ef7eb2e8f9f7 49 // set it as next interrupt and return
<> 144:ef7eb2e8f9f7 50 data->interface->set_interrupt(data->queue->head->timestamp);
<> 144:ef7eb2e8f9f7 51 return;
<> 144:ef7eb2e8f9f7 52 }
<> 144:ef7eb2e8f9f7 53 }
<> 144:ef7eb2e8f9f7 54 }
<> 144:ef7eb2e8f9f7 55
<> 144:ef7eb2e8f9f7 56 void ticker_insert_event(const ticker_data_t *const data, ticker_event_t *obj, timestamp_t timestamp, uint32_t id) {
<> 144:ef7eb2e8f9f7 57 /* disable interrupts for the duration of the function */
<> 144:ef7eb2e8f9f7 58 core_util_critical_section_enter();
<> 144:ef7eb2e8f9f7 59
<> 144:ef7eb2e8f9f7 60 // initialise our data
<> 144:ef7eb2e8f9f7 61 obj->timestamp = timestamp;
<> 144:ef7eb2e8f9f7 62 obj->id = id;
<> 144:ef7eb2e8f9f7 63
<> 144:ef7eb2e8f9f7 64 /* Go through the list until we either reach the end, or find
<> 144:ef7eb2e8f9f7 65 an element this should come before (which is possibly the
<> 144:ef7eb2e8f9f7 66 head). */
<> 144:ef7eb2e8f9f7 67 ticker_event_t *prev = NULL, *p = data->queue->head;
<> 144:ef7eb2e8f9f7 68 while (p != NULL) {
<> 144:ef7eb2e8f9f7 69 /* check if we come before p */
<> 144:ef7eb2e8f9f7 70 if ((int)(timestamp - p->timestamp) < 0) {
<> 144:ef7eb2e8f9f7 71 break;
<> 144:ef7eb2e8f9f7 72 }
<> 144:ef7eb2e8f9f7 73 /* go to the next element */
<> 144:ef7eb2e8f9f7 74 prev = p;
<> 144:ef7eb2e8f9f7 75 p = p->next;
<> 144:ef7eb2e8f9f7 76 }
<> 144:ef7eb2e8f9f7 77 /* if prev is NULL we're at the head */
<> 144:ef7eb2e8f9f7 78 if (prev == NULL) {
<> 144:ef7eb2e8f9f7 79 data->queue->head = obj;
<> 144:ef7eb2e8f9f7 80 data->interface->set_interrupt(timestamp);
<> 144:ef7eb2e8f9f7 81 } else {
<> 144:ef7eb2e8f9f7 82 prev->next = obj;
<> 144:ef7eb2e8f9f7 83 }
<> 144:ef7eb2e8f9f7 84 /* if we're at the end p will be NULL, which is correct */
<> 144:ef7eb2e8f9f7 85 obj->next = p;
<> 144:ef7eb2e8f9f7 86
<> 144:ef7eb2e8f9f7 87 core_util_critical_section_exit();
<> 144:ef7eb2e8f9f7 88 }
<> 144:ef7eb2e8f9f7 89
<> 144:ef7eb2e8f9f7 90 void ticker_remove_event(const ticker_data_t *const data, ticker_event_t *obj) {
<> 144:ef7eb2e8f9f7 91 core_util_critical_section_enter();
<> 144:ef7eb2e8f9f7 92
<> 144:ef7eb2e8f9f7 93 // remove this object from the list
<> 144:ef7eb2e8f9f7 94 if (data->queue->head == obj) {
<> 144:ef7eb2e8f9f7 95 // first in the list, so just drop me
<> 144:ef7eb2e8f9f7 96 data->queue->head = obj->next;
<> 144:ef7eb2e8f9f7 97 if (data->queue->head == NULL) {
<> 144:ef7eb2e8f9f7 98 data->interface->disable_interrupt();
<> 144:ef7eb2e8f9f7 99 } else {
<> 144:ef7eb2e8f9f7 100 data->interface->set_interrupt(data->queue->head->timestamp);
<> 144:ef7eb2e8f9f7 101 }
<> 144:ef7eb2e8f9f7 102 } else {
<> 144:ef7eb2e8f9f7 103 // find the object before me, then drop me
<> 144:ef7eb2e8f9f7 104 ticker_event_t* p = data->queue->head;
<> 144:ef7eb2e8f9f7 105 while (p != NULL) {
<> 144:ef7eb2e8f9f7 106 if (p->next == obj) {
<> 144:ef7eb2e8f9f7 107 p->next = obj->next;
<> 144:ef7eb2e8f9f7 108 break;
<> 144:ef7eb2e8f9f7 109 }
<> 144:ef7eb2e8f9f7 110 p = p->next;
<> 144:ef7eb2e8f9f7 111 }
<> 144:ef7eb2e8f9f7 112 }
<> 144:ef7eb2e8f9f7 113
<> 144:ef7eb2e8f9f7 114 core_util_critical_section_exit();
<> 144:ef7eb2e8f9f7 115 }
<> 144:ef7eb2e8f9f7 116
<> 144:ef7eb2e8f9f7 117 timestamp_t ticker_read(const ticker_data_t *const data)
<> 144:ef7eb2e8f9f7 118 {
<> 144:ef7eb2e8f9f7 119 return data->interface->read();
<> 144:ef7eb2e8f9f7 120 }
<> 144:ef7eb2e8f9f7 121
<> 144:ef7eb2e8f9f7 122 int ticker_get_next_timestamp(const ticker_data_t *const data, timestamp_t *timestamp)
<> 144:ef7eb2e8f9f7 123 {
<> 144:ef7eb2e8f9f7 124 int ret = 0;
<> 144:ef7eb2e8f9f7 125
<> 144:ef7eb2e8f9f7 126 /* if head is NULL, there are no pending events */
<> 144:ef7eb2e8f9f7 127 core_util_critical_section_enter();
<> 144:ef7eb2e8f9f7 128 if (data->queue->head != NULL) {
<> 144:ef7eb2e8f9f7 129 *timestamp = data->queue->head->timestamp;
<> 144:ef7eb2e8f9f7 130 ret = 1;
<> 144:ef7eb2e8f9f7 131 }
<> 144:ef7eb2e8f9f7 132 core_util_critical_section_exit();
<> 144:ef7eb2e8f9f7 133
<> 144:ef7eb2e8f9f7 134 return ret;
<> 144:ef7eb2e8f9f7 135 }