mbed library sources modified for open wear
Dependents: openwear-lifelogger-example
Fork of mbed-src by
targets/hal/TARGET_NXP/TARGET_LPC11UXX/pwmout_api.c
- Committer:
- janekm
- Date:
- 2014-09-16
- Revision:
- 310:6188e0254baa
- Parent:
- 274:6937b19af361
File content as of revision 310:6188e0254baa:
/* 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 "PeripheralPins.h" // For the Peripheral to Pin Definitions found in the individual Target's Platform #define TCR_CNT_EN 0x00000001 #define TCR_RESET 0x00000002 typedef struct { uint8_t timer; uint8_t mr; } timer_mr; static timer_mr pwm_timer_map[11] = { {0, 0}, {0, 1}, {0, 2}, {1, 0}, {1, 1}, {2, 0}, {2, 1}, {2, 2}, {3, 0}, {3, 1}, {3, 2}, }; static LPC_CTxxBx_Type *Timers[4] = { LPC_CT16B0, LPC_CT16B1, LPC_CT32B0, LPC_CT32B1 }; void pwmout_init(pwmout_t* obj, PinName pin) { // determine the channel PWMName pwm = (PWMName)pinmap_peripheral(pin, PinMap_PWM); MBED_ASSERT(pwm != (PWMName)NC); obj->pwm = pwm; // Timer registers timer_mr tid = pwm_timer_map[pwm]; LPC_CTxxBx_Type *timer = Timers[tid.timer]; // Disable timer timer->TCR = 0; // Power the correspondent timer LPC_SYSCON->SYSAHBCLKCTRL |= 1 << (tid.timer + 7); /* Enable PWM function */ timer->PWMC = (1 << 3)|(1 << 2)|(1 << 1)|(1 << 0); /* Reset Functionality on MR3 controlling the PWM period */ timer->MCR = 1 << 10; // default to 20ms: standard for servos, and fine for e.g. brightness control pwmout_period_ms(obj, 20); pwmout_write (obj, 0); // Wire pinout pinmap_pinout(pin, PinMap_PWM); } void pwmout_free(pwmout_t* obj) { // [TODO] } void pwmout_write(pwmout_t* obj, float value) { if (value < 0.0f) { value = 0.0; } else if (value > 1.0f) { value = 1.0; } timer_mr tid = pwm_timer_map[obj->pwm]; LPC_CTxxBx_Type *timer = Timers[tid.timer]; uint32_t t_off = timer->MR3 - (uint32_t)((float)(timer->MR3) * value); timer->MR[tid.mr] = t_off; } float pwmout_read(pwmout_t* obj) { timer_mr tid = pwm_timer_map[obj->pwm]; LPC_CTxxBx_Type *timer = Timers[tid.timer]; float v = (float)(timer->MR3 - timer->MR[tid.mr]) / (float)(timer->MR3); 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) { int i = 0; uint32_t period_ticks = (uint32_t)(((uint64_t)SystemCoreClock * (uint64_t)us) / (uint64_t)1000000); timer_mr tid = pwm_timer_map[obj->pwm]; LPC_CTxxBx_Type *timer = Timers[tid.timer]; uint32_t old_period_ticks = timer->MR3; // for 16bit timer, set prescaler to avoid overflow if (timer == LPC_CT16B0 || timer == LPC_CT16B1) { uint16_t high_period_ticks = period_ticks >> 16; timer->PR = high_period_ticks; period_ticks /= (high_period_ticks + 1); } timer->TCR = TCR_RESET; timer->MR3 = period_ticks; // Scale the pulse width to preserve the duty ratio if (old_period_ticks > 0) { for (i=0; i<3; i++) { uint32_t t_off = period_ticks - (uint32_t)(((uint64_t)timer->MR[i] * (uint64_t)period_ticks) / (uint64_t)old_period_ticks); timer->MR[i] = t_off; } } timer->TCR = TCR_CNT_EN; } 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) { timer_mr tid = pwm_timer_map[obj->pwm]; LPC_CTxxBx_Type *timer = Timers[tid.timer]; uint32_t t_on = (uint32_t)(((uint64_t)SystemCoreClock * (uint64_t)us) / (uint64_t)1000000 / (timer->PR + 1)); timer->TCR = TCR_RESET; if (t_on > timer->MR3) { pwmout_period_us(obj, us); t_on = (uint32_t)(((uint64_t)SystemCoreClock * (uint64_t)us) / (uint64_t)1000000 / (timer->PR + 1)); } uint32_t t_off = timer->MR3 - t_on; timer->MR[tid.mr] = t_off; timer->TCR = TCR_CNT_EN; }