add pwm support
This commit is contained in:
Mariano Alvira
parent
c967150038
commit
c7dc2a45a4
67
lib/include/pwm.h
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67
lib/include/pwm.h
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@ -0,0 +1,67 @@
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/*
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* Copyright (c) 2010, Mariano Alvira <mar@devl.org> and other contributors
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* to the MC1322x project (http://mc1322x.devl.org)
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the Institute nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* This file is part of libmc1322x: see http://mc1322x.devl.org
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* for details.
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*
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*
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*/
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#ifndef PWM_H
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#define PWM_H
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/* Initialize PWM output.
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timer_num = 0, 1, 2, 3
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rate = desired rate in Hz,
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duty = desired duty cycle. 0=always off, 65536=always on.
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enable_timer = whether to actually run the timer, versus just configuring it
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Returns actual PWM rate. */
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uint32_t pwm_init_ex(int timer_num, uint32_t rate, uint32_t duty, int enable_timer);
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/* Initialize PWM output, helper macros
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timer = TMR0, TMR1, TMR2, TMR2
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rate = desired rate in Hz,
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duty = desired duty cycle. 0=always off, 65536=always on.
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Returns actual PWM rate. */
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#define pwm_init(timer,rate,duty) pwm_init_ex(TMR_NUM(timer), rate, duty, 1)
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#define pwm_init_stopped(timer,rate,duty) pwm_init_ex(TMR_NUM(timer), rate, duty, 0)
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/* Change duty cycle. Safe to call at any time.
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timer_num = 0, 1, 2, 3
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duty = desired duty cycle. 0=always off, 65536=always on.
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*/
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void pwm_duty_ex(int timer_num, uint32_t duty);
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/* Change duty cycle. Safe to call at any time.
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timer = TMR0, TMR1, TMR2, TMR2
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duty = desired duty cycle. 0=always off, 65536=always on.
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*/
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#define pwm_duty(timer,duty) pwm_duty_ex(TMR_NUM(timer), duty)
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#endif
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254
lib/pwm.c
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254
lib/pwm.c
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@ -0,0 +1,254 @@
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/*
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* Copyright (c) 2010, Mariano Alvira <mar@devl.org> and other contributors
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* to the MC1322x project (http://mc1322x.devl.org)
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the Institute nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* This file is part of libmc1322x: see http://mc1322x.devl.org
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* for details.
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*
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*
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*/
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#include <mc1322x.h>
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#include <stdlib.h>
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#include "pwm.h"
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static struct {
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uint32_t period;
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uint32_t guard;
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uint32_t pad_forced;
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} pwm_info[4];
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static inline void pad_set_output(int timer_num) { // set to output (when in GPIO mode)
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switch (timer_num) {
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case 0: GPIO->DATA_SEL.TMR0_PIN = 1; GPIO->PAD_DIR.TMR0_PIN = 1; break;
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case 1: GPIO->DATA_SEL.TMR1_PIN = 1; GPIO->PAD_DIR.TMR1_PIN = 1; break;
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case 2: GPIO->DATA_SEL.TMR2_PIN = 1; GPIO->PAD_DIR.TMR2_PIN = 1; break;
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case 3: GPIO->DATA_SEL.TMR3_PIN = 1; GPIO->PAD_DIR.TMR3_PIN = 1; break;
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default: break;
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}
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}
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static inline void pad_set_zero(int timer_num) { // set to zero in GPIO mode
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switch (timer_num) {
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case 0: GPIO->DATA_RESET.TMR0_PIN = 1; GPIO->FUNC_SEL.TMR0_PIN = 0; break;
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case 1: GPIO->DATA_RESET.TMR1_PIN = 1; GPIO->FUNC_SEL.TMR1_PIN = 0; break;
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case 2: GPIO->DATA_RESET.TMR2_PIN = 1; GPIO->FUNC_SEL.TMR2_PIN = 0; break;
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case 3: GPIO->DATA_RESET.TMR3_PIN = 1; GPIO->FUNC_SEL.TMR3_PIN = 0; break;
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default: break;
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}
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}
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static inline void pad_set_one(int timer_num) { // set to one in GPIO mode
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switch (timer_num) {
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case 0: GPIO->DATA_SET.TMR0_PIN = 1; GPIO->FUNC_SEL.TMR0_PIN = 0; break;
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case 1: GPIO->DATA_SET.TMR1_PIN = 1; GPIO->FUNC_SEL.TMR1_PIN = 0; break;
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case 2: GPIO->DATA_SET.TMR2_PIN = 1; GPIO->FUNC_SEL.TMR2_PIN = 0; break;
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case 3: GPIO->DATA_SET.TMR3_PIN = 1; GPIO->FUNC_SEL.TMR3_PIN = 0; break;
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default: break;
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}
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}
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static inline void pad_set_normal(int timer_num) { // set to TMR OFLAG output
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switch (timer_num) {
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case 0: GPIO->FUNC_SEL.TMR0_PIN = 1; break;
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case 1: GPIO->FUNC_SEL.TMR1_PIN = 1; break;
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case 2: GPIO->FUNC_SEL.TMR2_PIN = 1; break;
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case 3: GPIO->FUNC_SEL.TMR3_PIN = 1; break;
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default: break;
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}
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}
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/* Initialize PWM output.
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timer_num = 0, 1, 2, 3
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rate = desired rate in Hz,
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duty = desired duty cycle. 0=always off, 65536=always on.
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enable_timer = whether to actually run the timer, versus just configuring it
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Returns actual PWM rate. */
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uint32_t pwm_init_ex(int timer_num, uint32_t rate, uint32_t duty, int enable_timer)
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{
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uint32_t actual_rate;
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volatile struct TMR_struct *timer = TMR_ADDR(timer_num);
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int log_divisor = 0;
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uint32_t period, guard;
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/* Turn timer off */
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TMR0->ENBL &= ~(1 << timer_num);
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/* Calculate optimal rate */
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for (log_divisor = 0; log_divisor < 8; log_divisor++)
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{
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int denom = (rate * (1 << log_divisor));
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period = (REF_OSC + denom/2) / denom;
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if (period <= 65535)
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break;
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}
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if (log_divisor >= 8)
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{
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period = 65535;
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log_divisor = 7;
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}
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/* Guard value (for safely changing duty cycle) should be
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about 32 CPU clocks. Calculate how many timer counts that
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is, based on prescaler */
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guard = 32 >> log_divisor;
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if (guard < 2) guard = 2;
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/* Period should be about 50% longer than guard */
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if (period < ((guard * 3) / 2))
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period = guard + 4;
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/* Store period, guard, actual rate */
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pwm_info[timer_num].period = period;
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pwm_info[timer_num].guard = guard;
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actual_rate = REF_OSC / (period * (1 << log_divisor));
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/* Set up timer */
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pwm_duty_ex(timer_num, duty); // sets CMPLD1, LOAD
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timer->SCTRLbits = (struct TMR_SCTRL) {
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.OEN = 1, // drive OFLAG
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};
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timer->CSCTRLbits = (struct TMR_CSCTRL) {
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.CL1 = 0x01, // Reload COMP1 when COMP1 matches
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};
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timer->COMP1 = timer->CMPLD1;
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timer->CNTR = timer->LOAD;
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timer->CTRLbits = (struct TMR_CTRL) {
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.COUNT_MODE = 1, // Count rising edge of primary source
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.PRIMARY_CNT_SOURCE = 8 + log_divisor, // Peripheral clock divided by (divisor)
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.LENGTH = 1, // At compare, reset to LOAD
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.OUTPUT_MODE = 6, // Set on COMP1, clear on rollover
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};
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pad_set_output(timer_num);
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pad_set_normal(timer_num);
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if (enable_timer) {
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TMR0->ENBL |= (1 << timer_num);
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}
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// printf("pwm timer %d, addr %p, requested rate %d, actual rate: %d, period %d, guard %d, divisor %d\r\n",
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// timer_num, timer, rate, actual_rate, period, guard, 1 << log_divisor);
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return actual_rate;
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}
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/* Change duty cycle. Safe to call at any time.
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timer_num = 0, 1, 2, 3
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duty = desired duty cycle. 0=always off, 65536=always on.
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*/
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void pwm_duty_ex(int timer_num, uint32_t duty)
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{
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uint16_t comp1, load;
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volatile struct TMR_struct *timer = TMR_ADDR(timer_num);
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uint32_t period = pwm_info[timer_num].period;
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duty = (duty * period + 32767) / 65536;
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/* We don't use the "variable PWM" mode described in the datasheet because
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there's no way to reliably change the duty cycle without potentially
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changing the period for one cycle, which will cause phase drifts.
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Instead, we use the "Set on compare, clear on rollover" output mode:
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waveform: |_________| |----------|
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counter: 0 COMP1 LOAD 65535
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The low portion of the wave is COMP1 cycles long. The
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compare changes the counter to LOAD, and so the high
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portion is (65536 - LOAD) cycles long.
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Now, we just have to make sure we're not about to hit COMP1
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before we change LOAD and COMPLD1. If (COMP1 - CNTR) is less
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than GUARD cycles, we wait for it to reload before changing.
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*/
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if (duty == 0) {
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pad_set_zero(timer_num);
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pwm_info[timer_num].pad_forced = 1;
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return;
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}
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if (duty >= period) {
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pad_set_one(timer_num);
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pwm_info[timer_num].pad_forced = 1;
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return;
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}
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if (pwm_info[timer_num].pad_forced) {
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pad_set_normal(timer_num);
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pwm_info[timer_num].pad_forced = 0;
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}
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comp1 = (period - duty) - 1;
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load = (65536 - duty);
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/* Disable interrupts */
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uint32_t old_INTCNTL = ITC->INTCNTL;
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ITC->INTCNTL = 0;
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if (TMR0->ENBL & (1 << timer_num))
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{
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/* Timer is enabled, so use the careful approach.
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Implemented in ASM so we can be sure of the cycle
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count */
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uint32_t tmp1, tmp2;
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asm volatile (//".arm \n\t"
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"1: \n\t"
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"ldrh %[tmp1], %[comp] \n\t" // load COMP1
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"ldrh %[tmp2], %[count] \n\t" // load CNTR
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"sub %[tmp1], %[tmp1], %[tmp2] \n\t" // subtract
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"lsl %[tmp1], %[tmp1], #16 \n\t" // clear high bits
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"lsr %[tmp1], %[tmp1], #16 \n\t"
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"cmp %[tmp1], %[guard] \n\t" // compare to GUARD
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"bls 1b \n\t" // if less, goto 1
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"strh %[ld1], %[cmpld] \n\t" // store CMPLD1
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"strh %[ld2], %[load] \n\t" // store LOAD
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: /* out */
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[tmp1] "=&l" (tmp1),
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[tmp2] "=&l" (tmp2),
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[cmpld] "=m" (timer->CMPLD1),
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[load] "=m" (timer->LOAD)
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: /* in */
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[comp] "m" (timer->COMP1),
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[count] "m" (timer->CNTR),
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[ld1] "l" (comp1),
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[ld2] "l" (load),
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[guard] "l" (pwm_info[timer_num].guard)
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: "memory"
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);
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} else {
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/* Just set it directly, timer isn't running */
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timer->CMPLD1 = comp1;
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timer->LOAD = load;
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}
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/* Re-enable interrupts */
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ITC->INTCNTL = old_INTCNTL;
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}
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@ -11,7 +11,9 @@ TARGETS := blink-red blink-green blink-blue blink-white blink-allio \
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tmr tmr-ints \
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sleep \
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printf \
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asm
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asm \
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adc \
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pwm
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# these targets are built with space reserved for variables needed by ROM services
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# this space is initialized with a rom call to rom_data_init
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85
tests/pwm.c
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85
tests/pwm.c
Normal file
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@ -0,0 +1,85 @@
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/*
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* Copyright (c) 2010, Mariano Alvira <mar@devl.org> and other contributors
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* to the MC1322x project (http://mc1322x.devl.org)
|
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* All rights reserved.
|
||||
*
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* Redistribution and use in source and binary forms, with or without
|
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* modification, are permitted provided that the following conditions
|
||||
* are met:
|
||||
* 1. Redistributions of source code must retain the above copyright
|
||||
* notice, this list of conditions and the following disclaimer.
|
||||
* 2. Redistributions in binary form must reproduce the above copyright
|
||||
* notice, this list of conditions and the following disclaimer in the
|
||||
* documentation and/or other materials provided with the distribution.
|
||||
* 3. Neither the name of the Institute nor the names of its contributors
|
||||
* may be used to endorse or promote products derived from this software
|
||||
* without specific prior written permission.
|
||||
*
|
||||
* THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
|
||||
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
||||
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
|
||||
* ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
|
||||
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
|
||||
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
|
||||
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
|
||||
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
||||
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
|
||||
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
|
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* SUCH DAMAGE.
|
||||
*
|
||||
* This file is part of libmc1322x: see http://mc1322x.devl.org
|
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* for details.
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*
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*
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*/
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#include <mc1322x.h>
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#include <board.h>
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#include <stdio.h>
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#include "config.h"
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#include "pwm.h"
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#include "rtc.h"
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int main(void)
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{
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int x = 32768;
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trim_xtal();
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uart1_init(INC,MOD,SAMP);
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rtc_init();
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printf("pwm test\r\n");
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pwm_init_stopped(TMR0, 12000000, x);
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pwm_init_stopped(TMR1, 12000000, x);
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TMR0->ENBL |= TMR_ENABLE_BIT(TMR0) | TMR_ENABLE_BIT(TMR1);
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for(;;) {
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printf("duty %d = %d%%\r\n", x, ((x * 100 + 32768) / 65536));
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switch(uart1_getc()) {
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case '[': x -= 1; break;
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case ']': x += 1; break;
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case '-': x -= 32; break;
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case '=': x += 32; break;
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case '_': x -= 512; break;
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case '+': x += 512; break;
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case '`': x = 65535 * 0/10; break;
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case '1': x = 65535 * 1/10; break;
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case '2': x = 65535 * 2/10; break;
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case '3': x = 65535 * 3/10; break;
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case '4': x = 65535 * 4/10; break;
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case '5': x = 65535 * 5/10; break;
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case '6': x = 65535 * 6/10; break;
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case '7': x = 65535 * 7/10; break;
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case '8': x = 65535 * 8/10; break;
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case '9': x = 65535 * 9/10; break;
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case '0': x = 65535 * 10/10; break;
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}
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x &= 65535;
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pwm_duty(TMR0, x);
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}
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}
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