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/* *****************************************************************************
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
* Created: 12/18/09 02:37:54
* Copyright (c) 2009 Perry L. Hung. All rights reserved.
*
* ****************************************************************************/
/**
* @file timers.c
*
* @brief General timer routines
*/
#include "libmaple.h"
#include "rcc.h"
#include "timers.h"
typedef struct {
volatile uint16_t CR1;
uint16_t RESERVED0;
volatile uint16_t CR2;
uint16_t RESERVED1;
volatile uint16_t SMCR;
uint16_t RESERVED2;
volatile uint16_t DIER;
uint16_t RESERVED3;
volatile uint16_t SR;
uint16_t RESERVED4;
volatile uint16_t EGR;
uint16_t RESERVED5;
volatile uint16_t CCMR1;
uint16_t RESERVED6;
volatile uint16_t CCMR2;
uint16_t RESERVED7;
volatile uint16_t CCER;
uint16_t RESERVED8;
volatile uint16_t CNT;
uint16_t RESERVED9;
volatile uint16_t PSC;
uint16_t RESERVED10;
volatile uint16_t ARR;
uint16_t RESERVED11;
volatile uint16_t RCR;
uint16_t RESERVED12;
volatile uint16_t CCR1;
uint16_t RESERVED13;
volatile uint16_t CCR2;
uint16_t RESERVED14;
volatile uint16_t CCR3;
uint16_t RESERVED15;
volatile uint16_t CCR4;
uint16_t RESERVED16;
volatile uint16_t BDTR; // Not used in general purpose timers
uint16_t RESERVED17; // Not used in general purpose timers
volatile uint16_t DCR;
uint16_t RESERVED18;
volatile uint16_t DMAR;
uint16_t RESERVED19;
} Timer;
void timer_init(uint8_t timer_num, uint16_t prescale) {
Timer *timer;
uint32_t is_advanced = 0;
ASSERT(timer_num > 0 && timer_num <= 4);
switch(timer_num) {
case 1:
timer = (Timer*)TIMER1_BASE;
rcc_enable_clk_timer1();
is_advanced = 1;
break;
case 2:
timer = (Timer*)TIMER2_BASE;
rcc_enable_clk_timer2();
break;
case 3:
timer = (Timer*)TIMER3_BASE;
rcc_enable_clk_timer3();
break;
case 4:
timer = (Timer*)TIMER4_BASE;
rcc_enable_clk_timer4();
break;
}
timer->CR1 = ARPE; // No clock division
// Do not buffer auto-reload preload
// Edge aligned
// Upcounter
// Do not stop counter at update event
// Update events enabled (etc, see bits [1:2])
// Counter disabled for now
timer->PSC = prescale; // Prescaling by prescale (duh)
timer->ARR = 0xFFFF; // Max reload cont
/* initialize all the channels to 50% duty cycle,
* TODO: none of them actually get output unless the gpio pin
* is set, this will probably consume a bit more power but
* we'll worry about that later. */
timer->CCR1 = 0x8FFF; // PWM start value
timer->CCMR1 |= 0x68; // PWM mode 1, enable preload register.
timer->CCER |= 0x001; // enable ch
timer->CCR2 = 0x8FFF; // PWM start value
timer->CCMR1 |= (0x68 << 8);// PWM mode 1, enable preload register.
timer->CCER |= 0x010; // enable ch
timer->CCR3 = 0x8FFF; // PWM start value
timer->CCMR2 |= 0x68; // PWM mode 1, enable preload register.
timer->CCER |= 0x100; // enable ch
timer->CCR4 = 0x8FFF; // PWM start value
timer->CCMR2 |= (0x68 << 8);// PWM mode 1, enable preload register.
timer->CCER |= 0x1000; // enable ch
/* Advanced timer? */
if (is_advanced) {
timer->BDTR = 0x8000; // moe enable
}
timer->DIER = 0; // disable update interrupt
timer->EGR = 1; // Initialize update event and shadow registers
timer->CR1 |= 1; // Enable timer
}
void timers_disable(void) {
Timer *timer;
int i;
Timer *timers[4] = {
(Timer*)TIMER1_BASE,
(Timer*)TIMER2_BASE,
(Timer*)TIMER3_BASE,
(Timer*)TIMER4_BASE,
};
for (i = 0; i < 4; i++) {
timer = timers[i];
timer->CR1 = 0;
timer->CCER = 0;
}
}
void timers_disable_channel(uint8 timer_num, uint8 channel) {
Timer *timer;
switch (timer_num) {
case 1:
timer = (Timer*)TIMER1_BASE;
break;
case 2:
timer = (Timer*)TIMER2_BASE;
break;
case 3:
timer = (Timer*)TIMER3_BASE;
break;
case 4:
timer = (Timer*)TIMER4_BASE;
break;
default:
ASSERT(0);
}
switch (channel) {
case 1:
timer->CCER &= ~(0x1);
break;
case 2:
timer->CCER &= ~(0x10);
break;
case 3:
timer->CCER &= ~(0x100);
break;
case 4:
timer->CCER &= ~(0x1000);
break;
default:
ASSERT(0);
}
}
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