d2abd471a5
The "timer" example is actually "the same" for both f1 and f4. Do a sanity sweep over the commentary, remove all vestiges that this was cloned from a motor control example, and synchronize both examples. Future work should extract the common portions "somewhere" but at least make them consistent for now.
172 lines
4.2 KiB
C
172 lines
4.2 KiB
C
/*
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* This file is part of the libopencm3 project.
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*
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* Copyright (C) 2015 Piotr Esden-Tempski <piotr@esden.net>
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* Copyright (C) 2015 Jack Ziesing <jziesing@gmail.com>
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*
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* This library is free software: you can redistribute it and/or modify
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* it under the terms of the GNU Lesser General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public License
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* along with this library. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <libopencm3/cm3/nvic.h>
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#include <libopencm3/stm32/rcc.h>
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#include <libopencm3/stm32/gpio.h>
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#include <libopencm3/stm32/timer.h>
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#include <libopencm3/stm32/exti.h>
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#include <libopencmsis/core_cm3.h>
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#ifndef ARRAY_LEN
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#define ARRAY_LEN(array) (sizeof((array))/sizeof((array)[0]))
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#endif
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uint16_t frequency_sequence[18] = {
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1000,
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500,
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1000,
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500,
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1000,
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500,
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2000,
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500,
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2000,
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500,
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2000,
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500,
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1000,
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500,
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1000,
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500,
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1000,
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5000,
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};
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uint16_t frequency_sel = 0;
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uint16_t compare_time;
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uint16_t new_time;
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uint16_t frequency;
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int debug = 0;
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static void clock_setup(void)
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{
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rcc_clock_setup_hse_3v3(&rcc_hse_8mhz_3v3[RCC_CLOCK_3V3_168MHZ]);
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}
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static void gpio_setup(void)
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{
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/* Enable GPIO clock for leds. */
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rcc_periph_clock_enable(RCC_GPIOD);
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/* Set GPIO12 (in GPIO port D) to 'output push-pull'. */
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gpio_mode_setup(GPIOD, GPIO_MODE_OUTPUT,
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GPIO_PUPD_NONE, GPIO12 | GPIO13);
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gpio_set(GPIOD, GPIO12);
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gpio_clear(GPIOD, GPIO13);
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}
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static void tim_setup(void)
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{
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/* Enable TIM2 clock. */
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rcc_periph_clock_enable(RCC_TIM2);
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/* Enable TIM2 interrupt. */
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nvic_enable_irq(NVIC_TIM2_IRQ);
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/* Reset TIM2 peripheral to defaults. */
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rcc_periph_reset_pulse(RST_TIM2);
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/* Timer global mode:
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* - No divider
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* - Alignment edge
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* - Direction up
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* (These are actually default values after reset above, so this call
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* is strictly unnecessary, but demos the api for alternative settings)
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*/
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timer_set_mode(TIM2, TIM_CR1_CKD_CK_INT,
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TIM_CR1_CMS_EDGE, TIM_CR1_DIR_UP);
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/*
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* Please take note that the clock source for STM32F4 timers
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* might not be the raw APB1/APB2 clocks. In various conditions they
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* are doubled. See the Reference Manual for full details!
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* In our case, TIM2 on APB1 is running at double frequency, so this
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* sets the prescaler to have the timer run at 10kHz
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*/
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timer_set_prescaler(TIM2, ((rcc_apb1_frequency * 2) / 10000));
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/* Disable preload. */
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timer_disable_preload(TIM2);
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timer_continuous_mode(TIM2);
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/* count full range, as we'll update compare value continuously */
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timer_set_period(TIM2, 65535);
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/* Set the initual output compare value for OC1. */
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timer_set_oc_value(TIM2, TIM_OC1, 1000);
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/* Counter enable. */
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timer_enable_counter(TIM2);
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/* Enable Channel 1 compare interrupt to recalculate compare values */
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timer_enable_irq(TIM2, TIM_DIER_CC1IE);
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}
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void tim2_isr(void)
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{
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if (timer_get_flag(TIM2, TIM_SR_CC1IF)) {
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/* Clear compare interrupt flag. */
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timer_clear_flag(TIM2, TIM_SR_CC1IF);
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/*
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* Get current timer value to calculate next
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* compare register value.
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*/
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compare_time = timer_get_counter(TIM2);
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/* Calculate and set the next compare value. */
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frequency = frequency_sequence[frequency_sel++];
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new_time = compare_time + frequency;
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timer_set_oc_value(TIM2, TIM_OC1, new_time);
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if (frequency_sel == ARRAY_LEN(frequency_sequence)) {
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frequency_sel = 0;
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}
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/* Toggle LED to indicate compare event. */
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gpio_toggle(GPIOD, GPIO12);
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gpio_toggle(GPIOD, GPIO13);
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}
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}
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int main(void)
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{
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clock_setup();
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gpio_setup();
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tim_setup();
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/* Loop calling Wait For Interrupt. In older pre cortex ARM this is
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* just equivalent to nop. On cortex it puts the cpu to sleep until
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* one of the three occurs:
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*
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* a non-masked interrupt occurs and is taken
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* an interrupt masked by PRIMASK becomes pending
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* a Debug Entry request
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*/
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while (1)
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__WFI(); /* Wait For Interrupt. */
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return 0;
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}
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