Mark Gottscho / HardwareTimersLib

Important changes to repositories hosted on mbed.com

Mbed hosted mercurial repositories are deprecated and are due to be permanently deleted in July 2026.

To keep a copy of this software download the repository Zip archive or clone locally using Mercurial.

It is also possible to export all your personal repositories from the account settings page.

Fork of HardwareTimersLib by Mark Gottscho

Timer_LPTMR.cpp@2:5056ec8c52e8, 2014-03-09 (annotated)

Committer:
mgottscho
Date:
Sun Mar 09 03:02:55 2014 +0000
Revision:
2:5056ec8c52e8
Parent:
1:7dde0e4d30da
Child:
7:78f6ee57d324
Refactored code and added new PIT timer support.

Who changed what in which revision?

UserRevisionLine numberNew contents of line
mgottscho 1:7dde0e4d30da 1 /* Timer_LPTMR.cpp
mgottscho 1:7dde0e4d30da 2 * Tested with mbed board: FRDM-KL46Z
mgottscho 1:7dde0e4d30da 3 * Author: Mark Gottscho
mgottscho 1:7dde0e4d30da 4 * mgottscho@ucla.edu
mgottscho 1:7dde0e4d30da 5 */
mgottscho 1:7dde0e4d30da 6
mgottscho 1:7dde0e4d30da 7 #include "mbed.h"
mgottscho 1:7dde0e4d30da 8 #include "HardwareTimer.h"
mgottscho 1:7dde0e4d30da 9 #include "Timer_LPTMR.h"
mgottscho 1:7dde0e4d30da 10 #include "PreciseTime.h"
mgottscho 1:7dde0e4d30da 11
mgottscho 1:7dde0e4d30da 12 //Init class static variable
mgottscho 1:7dde0e4d30da 13 bool Timer_LPTMR::__initialized_lptmr = false;
mgottscho 1:7dde0e4d30da 14 uint16_t Timer_LPTMR::__rolloverValue = 0xFFFF;
mgottscho 1:7dde0e4d30da 15 uint32_t Timer_LPTMR::__count = 0;
mgottscho 1:7dde0e4d30da 16
mgottscho 2:5056ec8c52e8 17 Timer_LPTMR::Timer_LPTMR(float tickValue) :
mgottscho 2:5056ec8c52e8 18 HardwareTimer(tickValue)
mgottscho 1:7dde0e4d30da 19 {
mgottscho 1:7dde0e4d30da 20 }
mgottscho 1:7dde0e4d30da 21
mgottscho 1:7dde0e4d30da 22 Timer_LPTMR::~Timer_LPTMR() {}
mgottscho 1:7dde0e4d30da 23
mgottscho 1:7dde0e4d30da 24 void Timer_LPTMR::disableTimer() {
mgottscho 1:7dde0e4d30da 25 if (!__valid)
mgottscho 1:7dde0e4d30da 26 return;
mgottscho 1:7dde0e4d30da 27
mgottscho 1:7dde0e4d30da 28 LPTMR0->CSR = 0; //Reset the LPTMR timer control/status register
mgottscho 1:7dde0e4d30da 29 __enabled = false;
mgottscho 1:7dde0e4d30da 30 }
mgottscho 1:7dde0e4d30da 31
mgottscho 1:7dde0e4d30da 32 uint32_t Timer_LPTMR::getTick() {
mgottscho 1:7dde0e4d30da 33 if (!__valid)
mgottscho 1:7dde0e4d30da 34 return 0;
mgottscho 1:7dde0e4d30da 35
mgottscho 1:7dde0e4d30da 36 //Get the raw time
mgottscho 1:7dde0e4d30da 37 __disable_irq();
mgottscho 1:7dde0e4d30da 38 LPTMR0->CNR = 0; //need to write to the register in order to read it due to buffering
mgottscho 1:7dde0e4d30da 39 uint16_t ticks = LPTMR0->CNR;
mgottscho 1:7dde0e4d30da 40 uint32_t count = __count;
mgottscho 1:7dde0e4d30da 41 __enable_irq();
mgottscho 1:7dde0e4d30da 42
mgottscho 1:7dde0e4d30da 43 //Convert to ticks
mgottscho 1:7dde0e4d30da 44 return (uint32_t) ((count * __rolloverValue) + ticks);
mgottscho 1:7dde0e4d30da 45 }
mgottscho 1:7dde0e4d30da 46
mgottscho 1:7dde0e4d30da 47
mgottscho 1:7dde0e4d30da 48 void Timer_LPTMR::__isr_lptmr() {
mgottscho 1:7dde0e4d30da 49 LPTMR0->CSR |= LPTMR_CSR_TCF_MASK; //Write 1 to TCF to clear the LPT timer compare flag
mgottscho 1:7dde0e4d30da 50 __set_lptmr(__rolloverValue); //Set timer again
mgottscho 1:7dde0e4d30da 51 __count++;
mgottscho 1:7dde0e4d30da 52 }
mgottscho 1:7dde0e4d30da 53
mgottscho 1:7dde0e4d30da 54 void Timer_LPTMR::__set_lptmr(uint16_t count) {
mgottscho 1:7dde0e4d30da 55 LPTMR0->CSR = 0; //Reset the timer control/status register
mgottscho 1:7dde0e4d30da 56 LPTMR0->CMR = count; //Set the compare register
mgottscho 1:7dde0e4d30da 57 LPTMR0->CSR |= LPTMR_CSR_TIE_MASK; //Enable interrupt
mgottscho 1:7dde0e4d30da 58 // LPTMR0->CSR |= LPTMR_CSR_TFC_MASK; //Set free-running mode
mgottscho 1:7dde0e4d30da 59 LPTMR0->CSR |= LPTMR_CSR_TEN_MASK; //Start the timer
mgottscho 1:7dde0e4d30da 60 }