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targets/TARGET_Freescale/TARGET_K20XX/TARGET_TEENSY3_1/us_ticker.c@175:b96e65c34a4d, 2017-10-02 (annotated)

Committer:
AnnaBridge
Date:
Mon Oct 02 15:33:19 2017 +0100
Revision:
175:b96e65c34a4d
Parent:
149:156823d33999 
This updates the lib to the mbed lib v 152

Who changed what in which revision?

UserRevisionLine numberNew contents of line
mbed_official 8:69ce7aaad4c4 1 /* mbed Microcontroller Library
mbed_official 8:69ce7aaad4c4 2 * Copyright (c) 2006-2015 ARM Limited
mbed_official 8:69ce7aaad4c4 3 *
mbed_official 8:69ce7aaad4c4 4 * Licensed under the Apache License, Version 2.0 (the "License");
mbed_official 8:69ce7aaad4c4 5 * you may not use this file except in compliance with the License.
mbed_official 8:69ce7aaad4c4 6 * You may obtain a copy of the License at
mbed_official 8:69ce7aaad4c4 7 *
mbed_official 8:69ce7aaad4c4 8 * http://www.apache.org/licenses/LICENSE-2.0
mbed_official 8:69ce7aaad4c4 9 *
mbed_official 8:69ce7aaad4c4 10 * Unless required by applicable law or agreed to in writing, software
mbed_official 8:69ce7aaad4c4 11 * distributed under the License is distributed on an "AS IS" BASIS,
mbed_official 8:69ce7aaad4c4 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
mbed_official 8:69ce7aaad4c4 13 * See the License for the specific language governing permissions and
mbed_official 8:69ce7aaad4c4 14 * limitations under the License.
mbed_official 8:69ce7aaad4c4 15 */
mbed_official 8:69ce7aaad4c4 16 #include <stddef.h>
mbed_official 8:69ce7aaad4c4 17 #include "us_ticker_api.h"
mbed_official 8:69ce7aaad4c4 18 #include "PeripheralNames.h"
mbed_official 8:69ce7aaad4c4 19 #include "clk_freqs.h"
mbed_official 8:69ce7aaad4c4 20
mbed_official 8:69ce7aaad4c4 21 static int us_ticker_inited = 0;
mbed_official 8:69ce7aaad4c4 22
mbed_official 8:69ce7aaad4c4 23 void us_ticker_init(void) {
mbed_official 8:69ce7aaad4c4 24 if (us_ticker_inited)
mbed_official 8:69ce7aaad4c4 25 return;
mbed_official 8:69ce7aaad4c4 26 us_ticker_inited = 1;
mbed_official 8:69ce7aaad4c4 27
mbed_official 8:69ce7aaad4c4 28 SIM->SCGC6 |= SIM_SCGC6_PIT_MASK; // Clock PIT
mbed_official 8:69ce7aaad4c4 29 PIT->MCR = 0; // Enable PIT
mbed_official 8:69ce7aaad4c4 30
mbed_official 8:69ce7aaad4c4 31 //Timer on PIT0+1, ticker on PIT 2+3
mbed_official 8:69ce7aaad4c4 32 //Init timer
mbed_official 8:69ce7aaad4c4 33 PIT->CHANNEL[1].LDVAL = 0xFFFFFFFF;
mbed_official 8:69ce7aaad4c4 34 PIT->CHANNEL[1].TCTRL = PIT_TCTRL_CHN_MASK | PIT_TCTRL_TEN_MASK; // Start timer 1, chained to timer 0
mbed_official 8:69ce7aaad4c4 35
mbed_official 8:69ce7aaad4c4 36 // Use channel 0 as a prescaler for channel 1
mbed_official 8:69ce7aaad4c4 37 uint32_t ldval = (bus_frequency() + 500000) / 1000000 - 1;
mbed_official 8:69ce7aaad4c4 38 PIT->CHANNEL[0].LDVAL = ldval;
mbed_official 8:69ce7aaad4c4 39 PIT->CHANNEL[0].TCTRL = PIT_TCTRL_TEN_MASK; // Start timer
mbed_official 8:69ce7aaad4c4 40
mbed_official 8:69ce7aaad4c4 41 //Init ticker
mbed_official 8:69ce7aaad4c4 42 PIT->CHANNEL[2].LDVAL = ldval;
mbed_official 8:69ce7aaad4c4 43 PIT->CHANNEL[2].TCTRL = PIT_TCTRL_TEN_MASK; // Start timer 2 as prescaler
mbed_official 8:69ce7aaad4c4 44
mbed_official 8:69ce7aaad4c4 45 NVIC_SetVector(PIT3_IRQn, (uint32_t)us_ticker_irq_handler);
mbed_official 8:69ce7aaad4c4 46 NVIC_EnableIRQ(PIT3_IRQn);
mbed_official 8:69ce7aaad4c4 47 }
mbed_official 8:69ce7aaad4c4 48
mbed_official 8:69ce7aaad4c4 49 /******************************************************************************
mbed_official 8:69ce7aaad4c4 50 * Timer for us timing.
mbed_official 8:69ce7aaad4c4 51 ******************************************************************************/
mbed_official 8:69ce7aaad4c4 52
mbed_official 8:69ce7aaad4c4 53 uint32_t us_ticker_read() {
mbed_official 8:69ce7aaad4c4 54 if (!us_ticker_inited)
mbed_official 8:69ce7aaad4c4 55 us_ticker_init();
mbed_official 8:69ce7aaad4c4 56
mbed_official 8:69ce7aaad4c4 57 return ~(PIT->CHANNEL[1].CVAL);
mbed_official 8:69ce7aaad4c4 58 }
mbed_official 8:69ce7aaad4c4 59
mbed_official 8:69ce7aaad4c4 60 /******************************************************************************
mbed_official 8:69ce7aaad4c4 61 * Ticker Event
mbed_official 8:69ce7aaad4c4 62 ******************************************************************************/
mbed_official 8:69ce7aaad4c4 63
mbed_official 8:69ce7aaad4c4 64 void us_ticker_disable_interrupt(void) {
mbed_official 8:69ce7aaad4c4 65 PIT->CHANNEL[3].TCTRL &= ~PIT_TCTRL_TIE_MASK;
mbed_official 8:69ce7aaad4c4 66 }
mbed_official 8:69ce7aaad4c4 67
mbed_official 8:69ce7aaad4c4 68 void us_ticker_clear_interrupt(void) {
mbed_official 8:69ce7aaad4c4 69 PIT->CHANNEL[3].TFLG = 1;
mbed_official 8:69ce7aaad4c4 70 }
mbed_official 8:69ce7aaad4c4 71
mbed_official 8:69ce7aaad4c4 72 void us_ticker_set_interrupt(timestamp_t timestamp) {
AnnaBridge 175:b96e65c34a4d 73 uint32_t delta = timestamp - us_ticker_read();
mbed_official 8:69ce7aaad4c4 74 PIT->CHANNEL[3].TCTRL = 0;
mbed_official 8:69ce7aaad4c4 75 PIT->CHANNEL[3].LDVAL = delta;
mbed_official 8:69ce7aaad4c4 76 PIT->CHANNEL[3].TCTRL = PIT_TCTRL_TIE_MASK | PIT_TCTRL_TEN_MASK | PIT_TCTRL_CHN_MASK;
mbed_official 8:69ce7aaad4c4 77
mbed_official 8:69ce7aaad4c4 78 }
AnnaBridge 175:b96e65c34a4d 79
AnnaBridge 175:b96e65c34a4d 80 void us_ticker_fire_interrupt(void)
AnnaBridge 175:b96e65c34a4d 81 {
AnnaBridge 175:b96e65c34a4d 82 NVIC_SetPendingIRQ(PIT3_IRQn);
AnnaBridge 175:b96e65c34a4d 83 }