Andrew Boyson / clock

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Dependents:   oldheating gps motorhome heating

timer.c@29:9332cf906aad, 2018-01-27 (annotated)

Committer:
andrewboyson
Date:
Sat Jan 27 12:17:09 2018 +0000
Revision:
29:9332cf906aad
Parent:
26:0421132e6eaf
Child:
30:212ca42b8779
libraries updated

Who changed what in which revision?

UserRevisionLine numberNew contents of line
andrewboyson 24:6c9833e2a049 1 #include <stdint.h>
andrewboyson 26:0421132e6eaf 2 #include <stdbool.h>
andrewboyson 24:6c9833e2a049 3
andrewboyson 29:9332cf906aad 4 #include "defs.h"
andrewboyson 25:81014a201736 5 #include "timer.h"
andrewboyson 24:6c9833e2a049 6
andrewboyson 26:0421132e6eaf 7 uint32_t TimerNowCount()
andrewboyson 26:0421132e6eaf 8 {
andrewboyson 26:0421132e6eaf 9 return LPC_TIM0->TC;
andrewboyson 24:6c9833e2a049 10 }
andrewboyson 26:0421132e6eaf 11 uint32_t TimerIntervalCount(uint32_t* pLastCount)
andrewboyson 24:6c9833e2a049 12 {
andrewboyson 24:6c9833e2a049 13 uint32_t thisCount = LPC_TIM0->TC;
andrewboyson 24:6c9833e2a049 14 uint32_t period = thisCount - *pLastCount;
andrewboyson 24:6c9833e2a049 15 *pLastCount = thisCount;
andrewboyson 24:6c9833e2a049 16 return period;
andrewboyson 24:6c9833e2a049 17 }
andrewboyson 24:6c9833e2a049 18 uint32_t TimerSinceCount(uint32_t startCount)
andrewboyson 24:6c9833e2a049 19 {
andrewboyson 24:6c9833e2a049 20 return LPC_TIM0->TC - startCount;
andrewboyson 24:6c9833e2a049 21 }
andrewboyson 24:6c9833e2a049 22 uint32_t TimerSinceMs(uint32_t startCount)
andrewboyson 24:6c9833e2a049 23 {
andrewboyson 24:6c9833e2a049 24 uint32_t count = LPC_TIM0->TC - startCount;
andrewboyson 25:81014a201736 25 return count / TIMER_COUNT_PER_MS;
andrewboyson 24:6c9833e2a049 26 }
andrewboyson 26:0421132e6eaf 27
andrewboyson 26:0421132e6eaf 28 static uint32_t secondsBaseCount = 0;
andrewboyson 26:0421132e6eaf 29
andrewboyson 26:0421132e6eaf 30 uint32_t TimerCountSinceLastSecond()
andrewboyson 26:0421132e6eaf 31 {
andrewboyson 26:0421132e6eaf 32 return LPC_TIM0->TC - secondsBaseCount;
andrewboyson 26:0421132e6eaf 33 }
andrewboyson 26:0421132e6eaf 34 int32_t TimerMultiplyFractionalPart(int32_t value, uint32_t timerCountSinceLastSecond)
andrewboyson 26:0421132e6eaf 35 {
andrewboyson 26:0421132e6eaf 36 int64_t fraction;
andrewboyson 26:0421132e6eaf 37
andrewboyson 26:0421132e6eaf 38 fraction = timerCountSinceLastSecond;
andrewboyson 26:0421132e6eaf 39 fraction <<= 32;
andrewboyson 26:0421132e6eaf 40 fraction /= TIMER_COUNT_PER_SECOND;
andrewboyson 26:0421132e6eaf 41
andrewboyson 26:0421132e6eaf 42 return (value * fraction) >> 32;
andrewboyson 26:0421132e6eaf 43 }
andrewboyson 26:0421132e6eaf 44
andrewboyson 26:0421132e6eaf 45 bool TimerTicked = false;
andrewboyson 26:0421132e6eaf 46
andrewboyson 26:0421132e6eaf 47 void TimerMain()
andrewboyson 26:0421132e6eaf 48 {
andrewboyson 26:0421132e6eaf 49 TimerTicked = TimerCountSinceLastSecond() > TIMER_COUNT_PER_SECOND;
andrewboyson 26:0421132e6eaf 50
andrewboyson 26:0421132e6eaf 51 if (TimerTicked) secondsBaseCount += TIMER_COUNT_PER_SECOND;
andrewboyson 26:0421132e6eaf 52 }
andrewboyson 26:0421132e6eaf 53 void TimerInit()
andrewboyson 26:0421132e6eaf 54 {
andrewboyson 26:0421132e6eaf 55 LPC_TIM0->TCR = 2; // 21.6.2 Timer Control Register - Reset TC and PC.
andrewboyson 26:0421132e6eaf 56 LPC_TIM0->CTCR = 0; // 21.6.3 Count Control Register - Timer mode
andrewboyson 26:0421132e6eaf 57 LPC_TIM0->PR = 0; // 21.6.5 Prescale register - Don't prescale 96MHz clock (divide by PR+1).
andrewboyson 26:0421132e6eaf 58 LPC_TIM0->MCR = 0; // 21.6.8 Match Control Register - no interrupt or reset
andrewboyson 26:0421132e6eaf 59 LPC_TIM0->TCR = 1; // 21.6.2 Timer Control Register - Enable TC and PC
andrewboyson 26:0421132e6eaf 60 }