+++ /dev/null
-/* 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 != (uint32_t)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);
-
- 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;
-
- // unhalt the counter:
- // - clearing bit 2 of the CTRL register
- pwm->CTRL &= ~(1 << 2);
-
- // 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 = 1.0;
- }
- uint32_t t_on = (uint32_t)((float)(obj->pwm->MATCHREL[obj->pwm_ch * 2]) * value);
- obj->pwm->MATCHREL[(obj->pwm_ch * 2) + 1] = t_on;
-}
-
-float pwmout_read(pwmout_t* obj)
-{
- uint32_t t_off = obj->pwm->MATCHREL[(obj->pwm_ch * 2) + 0];
- uint32_t t_on = obj->pwm->MATCHREL[(obj->pwm_ch * 2) + 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)
-{
- uint32_t t_off = obj->pwm->MATCHREL[(obj->pwm_ch * 2) + 0];
- uint32_t t_on = obj->pwm->MATCHREL[(obj->pwm_ch * 2) + 1];
- float v = (float)t_on/(float)t_off;
- obj->pwm->MATCHREL[(obj->pwm_ch * 2) + 0] = (uint32_t)us;
- obj->pwm->MATCHREL[(obj->pwm_ch * 2) + 1] = (uint32_t)((float)us * (float)v);
-}
-
-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)
-{
- obj->pwm->MATCHREL[(obj->pwm_ch * 2) + 1] = (uint32_t)us;
-}
-
-#endif