Mouse code for the MacroRat
Diff: mbed-dev/targets/TARGET_NXP/TARGET_LPC82X/pwmout_api.c
- Revision:
- 18:6a4db94011d3
diff -r f713758f6238 -r 6a4db94011d3 mbed-dev/targets/TARGET_NXP/TARGET_LPC82X/pwmout_api.c --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/mbed-dev/targets/TARGET_NXP/TARGET_LPC82X/pwmout_api.c Sun May 14 23:18:57 2017 +0000 @@ -0,0 +1,203 @@ +/* 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