mbed library sources modified for open wear
Dependents: openwear-lifelogger-example
Fork of mbed-src by
targets/hal/TARGET_NXP/TARGET_LPC408X/pwmout_api.c
- Committer:
- janekm
- Date:
- 2014-09-16
- Revision:
- 310:6188e0254baa
- Parent:
- 227:7bd0639b8911
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" #define TCR_CNT_EN 0x00000001 #define TCR_RESET 0x00000002 // PORT ID, PWM ID, Pin function static const PinMap PinMap_PWM[] = { {P1_2, PWM0_1, 3}, {P1_3, PWM0_2, 3}, {P1_5, PWM0_3, 3}, {P1_6, PWM0_4, 3}, {P1_7, PWM0_5, 3}, {P1_11, PWM0_6, 3}, {P1_18, PWM1_1, 2}, {P1_20, PWM1_2, 2}, {P1_21, PWM1_3, 2}, {P1_23, PWM1_4, 2}, {P1_24, PWM1_5, 2}, {P1_26, PWM1_6, 2}, {P2_0, PWM1_1, 1}, {P2_1, PWM1_2, 1}, {P2_2, PWM1_3, 1}, {P2_3, PWM1_4, 1}, {P2_4, PWM1_5, 1}, {P2_5, PWM1_6, 1}, {P3_16, PWM0_1, 2}, {P3_17, PWM0_2, 2}, {P3_18, PWM0_3, 2}, {P3_19, PWM0_4, 2}, {P3_20, PWM0_5, 2}, {P3_21, PWM0_6, 2}, {P3_24, PWM1_1, 2}, {P3_25, PWM1_2, 2}, {P3_26, PWM1_3, 2}, {P3_27, PWM1_4, 2}, {P3_28, PWM1_5, 2}, {P3_29, PWM1_6, 2}, {NC, NC, 0} }; static const uint32_t PWM_mr_offset[7] = { 0x18, 0x1C, 0x20, 0x24, 0x40, 0x44, 0x48 }; #define TCR_PWM_EN 0x00000008 static unsigned int pwm_clock_mhz; 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->channel = pwm; obj->pwm = LPC_PWM0; if (obj->channel > 6) { // PWM1 is used if pwm > 6 obj->channel -= 6; obj->pwm = LPC_PWM1; } obj->MR = (__IO uint32_t *)((uint32_t)obj->pwm + PWM_mr_offset[obj->channel]); // ensure the power is on if (obj->pwm == LPC_PWM0) { LPC_SC->PCONP |= 1 << 5; } else { LPC_SC->PCONP |= 1 << 6; } obj->pwm->PR = 0; // no pre-scale // ensure single PWM mode obj->pwm->MCR = 1 << 1; // reset TC on match 0 // enable the specific PWM output obj->pwm->PCR |= 1 << (8 + obj->channel); pwm_clock_mhz = PeripheralClock / 1000000; // 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; } // set channel match to percentage uint32_t v = (uint32_t)((float)(obj->pwm->MR0) * value); // workaround for PWM1[1] - Never make it equal MR0, else we get 1 cycle dropout if (v == obj->pwm->MR0) { v++; } *obj->MR = v; // accept on next period start obj->pwm->LER |= 1 << obj->channel; } float pwmout_read(pwmout_t* obj) { float v = (float)(*obj->MR) / (float)(obj->pwm->MR0); 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) { // calculate number of ticks uint32_t ticks = pwm_clock_mhz * us; // set reset obj->pwm->TCR = TCR_RESET; // set the global match register obj->pwm->MR0 = ticks; // Scale the pulse width to preserve the duty ratio if (obj->pwm->MR0 > 0) { *obj->MR = (*obj->MR * ticks) / obj->pwm->MR0; } // set the channel latch to update value at next period start obj->pwm->LER |= 1 << 0; // enable counter and pwm, clear reset obj->pwm->TCR = TCR_CNT_EN | TCR_PWM_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) { // calculate number of ticks uint32_t v = pwm_clock_mhz * us; // workaround for PWM1[1] - Never make it equal MR0, else we get 1 cycle dropout if (v == obj->pwm->MR0) { v++; } // set the match register value *obj->MR = v; // set the channel latch to update value at next period start obj->pwm->LER |= 1 << obj->channel; }