Mouse code for the MacroRat
mbed-dev/targets/TARGET_NXP/TARGET_LPC82X/pwmout_api.c
- Committer:
- sahilmgandhi
- Date:
- 2017-05-14
- Revision:
- 18:6a4db94011d3
File content as of revision 18:6a4db94011d3:
/* mbed Microcontroller Library * Copyright (c) 2006-2013 ARM Limited * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ #include "mbed_assert.h" #include "pwmout_api.h" #include "cmsis.h" #include "pinmap.h" #include "mbed_error.h" #if DEVICE_PWMOUT // bit flags for used SCTs static unsigned char sct_used = 0; static int get_available_sct() { int i; for (i = 0; i < 4; i++) { if ((sct_used & (1 << i)) == 0) return i; } return -1; } void pwmout_init(pwmout_t* obj, PinName pin) { MBED_ASSERT(pin != (PinName)NC); int sct_n = get_available_sct(); if (sct_n == -1) { error("No available SCT"); } sct_used |= (1 << sct_n); obj->pwm = (LPC_SCT_Type*)LPC_SCT; obj->pwm_ch = sct_n; LPC_SCT_Type* pwm = obj->pwm; // Enable the SCT clock LPC_SYSCON->SYSAHBCLKCTRL |= (1 << 8); // Clear peripheral reset the SCT: LPC_SYSCON->PRESETCTRL |= (1 << 8); switch(sct_n) { case 0: // SCT_OUT0 LPC_SWM->PINASSIGN[7] &= ~0xFF000000; LPC_SWM->PINASSIGN[7] |= ((pin >> PIN_SHIFT) << 24); break; case 1: // SCT_OUT1 LPC_SWM->PINASSIGN[8] &= ~0x000000FF; LPC_SWM->PINASSIGN[8] |= (pin >> PIN_SHIFT); break; case 2: // SCT2_OUT2 LPC_SWM->PINASSIGN[8] &= ~0x0000FF00; LPC_SWM->PINASSIGN[8] |= ((pin >> PIN_SHIFT) << 8); break; case 3: // SCT3_OUT3 LPC_SWM->PINASSIGN[8] &= ~0x00FF0000; LPC_SWM->PINASSIGN[8] |= ((pin >> PIN_SHIFT) << 16); break; default: break; } // Unified 32-bit counter, autolimit pwm->CONFIG |= ((0x3 << 17) | 0x01); // halt and clear the counter pwm->CTRL |= (1 << 2) | (1 << 3); // System Clock -> us_ticker (1)MHz pwm->CTRL &= ~(0x7F << 5); pwm->CTRL |= (((SystemCoreClock/1000000 - 1) & 0x7F) << 5); // Set event number pwm->OUT[sct_n].SET = (1 << ((sct_n * 2) + 0)); pwm->OUT[sct_n].CLR = (1 << ((sct_n * 2) + 1)); pwm->EVENT[(sct_n * 2) + 0].CTRL = (1 << 12) | ((sct_n * 2) + 0); // match event pwm->EVENT[(sct_n * 2) + 0].STATE = 0xFFFFFFFF; pwm->EVENT[(sct_n * 2) + 1].CTRL = (1 << 12) | ((sct_n * 2) + 1); pwm->EVENT[(sct_n * 2) + 1].STATE = 0xFFFFFFFF; // default to 20ms: standard for servos, and fine for e.g. brightness control pwmout_period_ms(obj, 20); pwmout_write (obj, 0); } void pwmout_free(pwmout_t* obj) { // Disable the SCT clock LPC_SYSCON->SYSAHBCLKCTRL &= ~(1 << 8); sct_used &= ~(1 << obj->pwm_ch); } void pwmout_write(pwmout_t* obj, float value) { if (value < 0.0f) { value = 0.0; } else if (value > 1.0f) { value = 1.0f; } uint32_t t_on = (uint32_t)((float)(obj->pwm->MATCHREL[obj->pwm_ch * 2] + 1) * value); if (t_on > 0) { // duty is not 0% if (value != 1.0f) { // duty is not 100% obj->pwm->MATCHREL[(obj->pwm_ch * 2) + 1] = t_on - 1; // unhalt the counter obj->pwm->CTRL &= ~(1 << 2); } else { // duty is 100% // halt and clear the counter obj->pwm->CTRL |= (1 << 2) | (1 << 3); // output level tied to high obj->pwm->OUTPUT |= (1 << obj->pwm_ch); } } else { // duty is 0% // halt and clear the counter obj->pwm->CTRL |= (1 << 2) | (1 << 3); // output level tied to low obj->pwm->OUTPUT &= ~(1 << obj->pwm_ch); } } float pwmout_read(pwmout_t* obj) { uint32_t t_off = obj->pwm->MATCHREL[(obj->pwm_ch * 2) + 0] + 1; uint32_t t_on = obj->pwm->MATCHREL[(obj->pwm_ch * 2) + 1] + 1; float v = (float)t_on/(float)t_off; return (v > 1.0f) ? (1.0f) : (v); } void pwmout_period(pwmout_t* obj, float seconds) { pwmout_period_us(obj, seconds * 1000000.0f); } void pwmout_period_ms(pwmout_t* obj, int ms) { pwmout_period_us(obj, ms * 1000); } // Set the PWM period, keeping the duty cycle the same. void pwmout_period_us(pwmout_t* obj, int us) { // The period are off by one for MATCHREL, so +1 to get actual value uint32_t t_off = obj->pwm->MATCHREL[(obj->pwm_ch * 2) + 0] + 1; uint32_t t_on = obj->pwm->MATCHREL[(obj->pwm_ch * 2) + 1] + 1; float v = (float)t_on/(float)t_off; obj->pwm->MATCHREL[(obj->pwm_ch * 2) + 0] = (uint32_t)us - 1; if (us > 0) { // PWM period is not 0 obj->pwm->MATCHREL[(obj->pwm_ch * 2) + 1] = (uint32_t)((float)us * (float)v) - 1; // unhalt the counter obj->pwm->CTRL &= ~(1 << 2); } else { // PWM period is 0 // halt and clear the counter obj->pwm->CTRL |= (1 << 2) | (1 << 3); // output level tied to low obj->pwm->OUTPUT &= ~(1 << obj->pwm_ch); } } void pwmout_pulsewidth(pwmout_t* obj, float seconds) { pwmout_pulsewidth_us(obj, seconds * 1000000.0f); } void pwmout_pulsewidth_ms(pwmout_t* obj, int ms) { pwmout_pulsewidth_us(obj, ms * 1000); } void pwmout_pulsewidth_us(pwmout_t* obj, int us) { if (us > 0) { // PWM peried is not 0 obj->pwm->MATCHREL[(obj->pwm_ch * 2) + 1] = (uint32_t)us - 1; obj->pwm->CTRL &= ~(1 << 2); } else { //PWM period is 0 // halt and clear the counter obj->pwm->CTRL |= (1 << 2) | (1 << 3); // output level tied to low obj->pwm->OUTPUT &= ~(1 << obj->pwm_ch); } } #endif