Andrew Boyson / clock

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Dependents:   oldheating gps motorhome heating

timer/timer.c@39:5b594b1b6a0a, 2018-12-03 (annotated)

Committer:
andrewboyson
Date:
Mon Dec 03 12:50:10 2018 +0000
Revision:
39:5b594b1b6a0a
Parent:
38:25b2a3c494aa 
Minor changes to names in timer

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 38:25b2a3c494aa 4 #include "timer.h"
andrewboyson 24:6c9833e2a049 5
andrewboyson 30:212ca42b8779 6 #define TCR (*((volatile unsigned *) 0x40004004))
andrewboyson 30:212ca42b8779 7 #define TC (*((volatile unsigned *) 0x40004008))
andrewboyson 30:212ca42b8779 8 #define PR (*((volatile unsigned *) 0x4000400C))
andrewboyson 30:212ca42b8779 9 #define MCR (*((volatile unsigned *) 0x40004014))
andrewboyson 30:212ca42b8779 10 #define CTCR (*((volatile unsigned *) 0x40004070))
andrewboyson 30:212ca42b8779 11
andrewboyson 39:5b594b1b6a0a 12 uint32_t TimerCount()
andrewboyson 26:0421132e6eaf 13 {
andrewboyson 30:212ca42b8779 14 return TC;
andrewboyson 24:6c9833e2a049 15 }
andrewboyson 39:5b594b1b6a0a 16 uint32_t TimerSinceRepetitive(uint32_t* pLastCount)
andrewboyson 24:6c9833e2a049 17 {
andrewboyson 30:212ca42b8779 18 uint32_t thisCount = TC;
andrewboyson 24:6c9833e2a049 19 uint32_t period = thisCount - *pLastCount;
andrewboyson 24:6c9833e2a049 20 *pLastCount = thisCount;
andrewboyson 24:6c9833e2a049 21 return period;
andrewboyson 24:6c9833e2a049 22 }
andrewboyson 39:5b594b1b6a0a 23 uint32_t TimerSinceCount(uint32_t lastCount)
andrewboyson 24:6c9833e2a049 24 {
andrewboyson 39:5b594b1b6a0a 25 return TC - lastCount;
andrewboyson 24:6c9833e2a049 26 }
andrewboyson 39:5b594b1b6a0a 27 uint32_t TimerSinceMs(uint32_t lastCount)
andrewboyson 24:6c9833e2a049 28 {
andrewboyson 39:5b594b1b6a0a 29 uint32_t count = TC - lastCount;
andrewboyson 25:81014a201736 30 return count / TIMER_COUNT_PER_MS;
andrewboyson 24:6c9833e2a049 31 }
andrewboyson 26:0421132e6eaf 32
andrewboyson 39:5b594b1b6a0a 33 bool TimerRepetitiveTick(uint32_t* pLastCount, uint32_t interval)
andrewboyson 26:0421132e6eaf 34 {
andrewboyson 39:5b594b1b6a0a 35 if (TC - *pLastCount >= interval) //All unsigned wrap around arithmetic
andrewboyson 33:b9e3c06e7dab 36 {
andrewboyson 39:5b594b1b6a0a 37 *pLastCount += interval;
andrewboyson 33:b9e3c06e7dab 38 return true;
andrewboyson 33:b9e3c06e7dab 39 }
andrewboyson 33:b9e3c06e7dab 40 return false;
andrewboyson 26:0421132e6eaf 41 }
andrewboyson 33:b9e3c06e7dab 42
andrewboyson 39:5b594b1b6a0a 43 int32_t TimerMultiplyFractionalPart(int32_t value, uint32_t countSinceLast, uint32_t interval)
andrewboyson 26:0421132e6eaf 44 {
andrewboyson 26:0421132e6eaf 45 int64_t fraction;
andrewboyson 26:0421132e6eaf 46
andrewboyson 39:5b594b1b6a0a 47 fraction = countSinceLast;
andrewboyson 26:0421132e6eaf 48 fraction <<= 32;
andrewboyson 33:b9e3c06e7dab 49 fraction /= interval;
andrewboyson 26:0421132e6eaf 50
andrewboyson 26:0421132e6eaf 51 return (value * fraction) >> 32;
andrewboyson 26:0421132e6eaf 52 }
andrewboyson 26:0421132e6eaf 53
andrewboyson 26:0421132e6eaf 54 void TimerInit()
andrewboyson 26:0421132e6eaf 55 {
andrewboyson 30:212ca42b8779 56 TCR = 2; // 21.6.2 Timer Control Register - Reset TC and PC.
andrewboyson 30:212ca42b8779 57 CTCR = 0; // 21.6.3 Count Control Register - Timer mode
andrewboyson 30:212ca42b8779 58 PR = 0; // 21.6.5 Prescale register - Don't prescale 96MHz clock (divide by PR+1).
andrewboyson 30:212ca42b8779 59 MCR = 0; // 21.6.8 Match Control Register - no interrupt or reset
andrewboyson 30:212ca42b8779 60 TCR = 1; // 21.6.2 Timer Control Register - Enable TC and PC
andrewboyson 26:0421132e6eaf 61 }