Geofrey Marcel / FastPWM

Fork of Erik Olieman's FastPWM library created to add the targets I need.

Fork of FastPWM by Erik -

Device/FastPWM_LPC11U24.cpp@12:4600daab8a83, 2014-07-20 (annotated)

Committer:
Sissors
Date:
Sun Jul 20 12:49:21 2014 +0000
Revision:
12:4600daab8a83
Parent:
10:36362e9067b0 
Preparation for Nucleo devices: Added option to have a device specific container with variables (such as pointer to match registers, since nucleo pwmout class lacks those).

; And practised on the LPC11u24 to implement it.

Who changed what in which revision?

UserRevisionLine numberNew contents of line
Sissors 4:a7b9f778c4b4 1 #ifdef TARGET_LPC11U24
Sissors 4:a7b9f778c4b4 2
Sissors 4:a7b9f778c4b4 3 #include "FastPWM.h"
Sissors 4:a7b9f778c4b4 4
Sissors 12:4600daab8a83 5 #define PWM_MR (*(((fastpwm_struct*)fast_obj)->MR))
Sissors 12:4600daab8a83 6 #define PWM_TIMER (((fastpwm_struct*)fast_obj)->timer)
Sissors 12:4600daab8a83 7
Sissors 12:4600daab8a83 8 typedef struct {
Sissors 12:4600daab8a83 9 __IO uint32_t *MR;
Sissors 12:4600daab8a83 10 LPC_CTxxBx_Type *timer;
Sissors 12:4600daab8a83 11 } fastpwm_struct;
Sissors 12:4600daab8a83 12
Sissors 4:a7b9f778c4b4 13 typedef struct {
Sissors 4:a7b9f778c4b4 14 uint8_t timer;
Sissors 4:a7b9f778c4b4 15 uint8_t mr;
Sissors 4:a7b9f778c4b4 16 } timer_mr;
Sissors 4:a7b9f778c4b4 17
Sissors 4:a7b9f778c4b4 18 static timer_mr pwm_timer_map[11] = {
Sissors 4:a7b9f778c4b4 19 {0, 0}, {0, 1}, {0, 2},
Sissors 4:a7b9f778c4b4 20 {1, 0}, {1, 1},
Sissors 4:a7b9f778c4b4 21 {2, 0}, {2, 1}, {2, 2},
Sissors 4:a7b9f778c4b4 22 {3, 0}, {3, 1}, {3, 2},
Sissors 4:a7b9f778c4b4 23 };
Sissors 4:a7b9f778c4b4 24
Sissors 4:a7b9f778c4b4 25 static LPC_CTxxBx_Type *Timers[4] = {
Sissors 4:a7b9f778c4b4 26 LPC_CT16B0, LPC_CT16B1,
Sissors 4:a7b9f778c4b4 27 LPC_CT32B0, LPC_CT32B1
Sissors 4:a7b9f778c4b4 28 };
Sissors 4:a7b9f778c4b4 29
Sissors 4:a7b9f778c4b4 30
Sissors 4:a7b9f778c4b4 31 void FastPWM::initFastPWM( void ) {
Sissors 12:4600daab8a83 32 fast_obj = new fastpwm_struct;
Sissors 12:4600daab8a83 33 timer_mr tid = pwm_timer_map[_pwm.pwm];
Sissors 12:4600daab8a83 34 PWM_TIMER = Timers[tid.timer];
Sissors 12:4600daab8a83 35 (((fastpwm_struct*)fast_obj)->MR) = &PWM_TIMER->MR[tid.mr];
Sissors 4:a7b9f778c4b4 36
Sissors 4:a7b9f778c4b4 37 if (tid.timer < 2)
Sissors 4:a7b9f778c4b4 38 //16-bit timer
Sissors 4:a7b9f778c4b4 39 bits = 16;
Sissors 4:a7b9f778c4b4 40 else
Sissors 4:a7b9f778c4b4 41 //32-bit timer
Sissors 7:1b5df740bcd7 42 bits = 32;
Sissors 4:a7b9f778c4b4 43 }
Sissors 4:a7b9f778c4b4 44
Sissors 4:a7b9f778c4b4 45 void FastPWM::pulsewidth_ticks( uint32_t ticks ) {
Sissors 7:1b5df740bcd7 46 if (ticks)
Sissors 12:4600daab8a83 47 PWM_MR = PWM_TIMER->MR3 - ticks; //They inverted PWM on the 11u24
Sissors 7:1b5df740bcd7 48 else
Sissors 12:4600daab8a83 49 PWM_MR = 0xFFFFFFFF; //If MR3 = ticks 1 clock cycle wide errors appear, this prevents that (unless MR3 = max).
Sissors 4:a7b9f778c4b4 50 }
Sissors 4:a7b9f778c4b4 51
Sissors 12:4600daab8a83 52 void FastPWM::period_ticks( uint32_t ticks ) {
Sissors 12:4600daab8a83 53 PWM_TIMER->TCR = 0x02;
Sissors 12:4600daab8a83 54 PWM_TIMER->MR3 = ticks;
Sissors 12:4600daab8a83 55 PWM_TIMER->TCR = 0x01;
Sissors 4:a7b9f778c4b4 56 }
Sissors 4:a7b9f778c4b4 57
Sissors 4:a7b9f778c4b4 58 uint32_t FastPWM::getPeriod( void ) {
Sissors 12:4600daab8a83 59 return PWM_TIMER->MR3;
Sissors 4:a7b9f778c4b4 60 }
Sissors 4:a7b9f778c4b4 61
Sissors 4:a7b9f778c4b4 62 uint32_t FastPWM::setPrescaler(uint32_t reqScale) {
Sissors 4:a7b9f778c4b4 63 //If 32-bit, disable auto-scaling, return 1
Sissors 4:a7b9f778c4b4 64 if (bits == 32) {
Sissors 4:a7b9f778c4b4 65 dynamicPrescaler = false;
Sissors 4:a7b9f778c4b4 66 return 1;
Sissors 4:a7b9f778c4b4 67 }
Sissors 4:a7b9f778c4b4 68
Sissors 4:a7b9f778c4b4 69 //Else 16-bit timer:
Sissors 4:a7b9f778c4b4 70 if (reqScale == 0)
Sissors 4:a7b9f778c4b4 71 //Return prescaler
Sissors 12:4600daab8a83 72 return PWM_TIMER->PR + 1;
Sissors 4:a7b9f778c4b4 73 if (reqScale > (uint32_t)(1<<16))
Sissors 4:a7b9f778c4b4 74 reqScale = 1<<16;
Sissors 4:a7b9f778c4b4 75 //Else set prescaler, we have to substract one from reqScale since a 0 in PCVAL is prescaler of 1
Sissors 12:4600daab8a83 76 PWM_TIMER->PR = reqScale - 1;
Sissors 4:a7b9f778c4b4 77
Sissors 4:a7b9f778c4b4 78 return reqScale;
Sissors 4:a7b9f778c4b4 79 }
Sissors 4:a7b9f778c4b4 80
Sissors 4:a7b9f778c4b4 81 #endif