Ernesto Palacios / FastPWM

Ley de Ohm

Fork of FastPWM by Erik -

Device/FastPWM_LPC_SCT.cpp@32:c87e19d668e2, 2017-05-09 (annotated)

Committer:
Yo_Robot
Date:
Tue May 09 16:34:49 2017 +0000
Revision:
32:c87e19d668e2
Parent:
30:87e38b846651 
modified version do not use

Who changed what in which revision?

UserRevisionLine numberNew contents of line
Sissors 29:3e4d3b900850 1 //For targets which use the SCT
Sissors 29:3e4d3b900850 2 #if defined(TARGET_LPC81X) || defined(TARGET_LPC82X)
Sissors 29:3e4d3b900850 3
Sissors 29:3e4d3b900850 4 #ifdef TARGET_LPC82X
Sissors 29:3e4d3b900850 5 #define CTRL_U CTRL
Sissors 29:3e4d3b900850 6 #endif
Sissors 29:3e4d3b900850 7
Sissors 29:3e4d3b900850 8 #include "FastPWM.h"
Sissors 29:3e4d3b900850 9
Sissors 29:3e4d3b900850 10 void FastPWM::initFastPWM( void ) {
Sissors 29:3e4d3b900850 11 //Mbed uses the timer as a single unified 32-bit timer, who are we to argue with this, and it is easier
Sissors 29:3e4d3b900850 12 bits = 32;
Sissors 29:3e4d3b900850 13
Sissors 30:87e38b846651 14 #ifdef TARGET_LPC82X
Sissors 30:87e38b846651 15 //The mbed lib uses the PWM peripheral slightly different, which is irritating. This sets it bck to the LPC81X
Sissors 30:87e38b846651 16 _pwm.pwm->EVENT[_pwm.pwm_ch + 1].CTRL = (1 << 12) | (_pwm.pwm_ch + 1); // Event_n on Match_n
Sissors 30:87e38b846651 17 _pwm.pwm->EVENT[_pwm.pwm_ch + 1].STATE = 0xFFFFFFFF; // All states
Sissors 30:87e38b846651 18 _pwm.pwm->OUT[_pwm.pwm_ch].SET = (1 << 0); // All PWM channels are SET on Event_0
Sissors 30:87e38b846651 19 _pwm.pwm->OUT[_pwm.pwm_ch].CLR = (1 << (_pwm.pwm_ch + 1)); // PWM ch is CLRed on Event_(ch+1)
Sissors 30:87e38b846651 20 #endif
Sissors 30:87e38b846651 21
Sissors 29:3e4d3b900850 22 //With 32-bit we fix prescaler to 1
Sissors 29:3e4d3b900850 23 _pwm.pwm->CTRL_U |= (1 << 2) | (1 << 3);
Sissors 29:3e4d3b900850 24 _pwm.pwm->CTRL_U &= ~(0x7F << 5);
Sissors 29:3e4d3b900850 25 _pwm.pwm->CTRL_U &= ~(1 << 2);
Sissors 29:3e4d3b900850 26
Sissors 29:3e4d3b900850 27 }
Sissors 29:3e4d3b900850 28
Sissors 29:3e4d3b900850 29 void FastPWM::pulsewidth_ticks( uint32_t ticks ) {
Sissors 29:3e4d3b900850 30 #ifdef TARGET_LPC81X
Sissors 29:3e4d3b900850 31 _pwm.pwm->MATCHREL[_pwm.pwm_ch + 1].U = ticks;
Sissors 29:3e4d3b900850 32 #else
Sissors 29:3e4d3b900850 33 _pwm.pwm->MATCHREL[_pwm.pwm_ch + 1] = ticks;
Sissors 29:3e4d3b900850 34 #endif
Sissors 29:3e4d3b900850 35 }
Sissors 29:3e4d3b900850 36
Sissors 29:3e4d3b900850 37 void FastPWM::period_ticks( uint32_t ticks ) {
Sissors 29:3e4d3b900850 38 #ifdef TARGET_LPC81X
Sissors 29:3e4d3b900850 39 _pwm.pwm->MATCHREL[0].U = ticks;
Sissors 29:3e4d3b900850 40 #else
Sissors 29:3e4d3b900850 41 _pwm.pwm->MATCHREL[0] = ticks;
Sissors 29:3e4d3b900850 42 #endif
Sissors 29:3e4d3b900850 43 }
Sissors 29:3e4d3b900850 44
Sissors 29:3e4d3b900850 45 uint32_t FastPWM::getPeriod( void ) {
Sissors 29:3e4d3b900850 46 #ifdef TARGET_LPC81X
Sissors 29:3e4d3b900850 47 return _pwm.pwm->MATCHREL[0].U;
Sissors 29:3e4d3b900850 48 #else
Sissors 29:3e4d3b900850 49 return _pwm.pwm->MATCHREL[0];
Sissors 29:3e4d3b900850 50 #endif
Sissors 29:3e4d3b900850 51 }
Sissors 29:3e4d3b900850 52
Sissors 29:3e4d3b900850 53 //Maybe implemented later, but needing to change the prescaler for a 32-bit
Sissors 29:3e4d3b900850 54 //timer used in PWM mode is kinda unlikely.
Sissors 29:3e4d3b900850 55 //If you really need to do it, rejoice, you can make it run so slow a period is over 40,000 year
Sissors 29:3e4d3b900850 56 uint32_t FastPWM::setPrescaler(uint32_t reqScale) {
Sissors 29:3e4d3b900850 57 //Disable dynamic prescaling
Sissors 29:3e4d3b900850 58 dynamicPrescaler = false;
Sissors 29:3e4d3b900850 59
Sissors 29:3e4d3b900850 60 return 1;
Sissors 29:3e4d3b900850 61 }
Sissors 29:3e4d3b900850 62
Sissors 29:3e4d3b900850 63 #endif