d8757ab1fc
This example is a merge of Chuck McManis's example for F4 and onnokort's system clock setting test blink example for demonstration issue, corrected in #224. The LED in any available clock setting flashes four times per second.
84 lines
2.3 KiB
C
84 lines
2.3 KiB
C
/*
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* This file is part of the libopencm3 project.
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*
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* Copyright (C) 2013 Chuck McManis <cmcmanis@mcmanis.com>
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* Copyright (C) 2013 Onno Kortmann <onno@gmx.net>
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* Copyright (C) 2013 Frantisek Burian <BuFran@seznam.cz> (merge)
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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/stm32/rcc.h>
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#include <libopencm3/stm32/gpio.h>
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#include <libopencm3/cm3/nvic.h>
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#include <libopencm3/cm3/systick.h>
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/* Called when systick fires */
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void sys_tick_handler(void)
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{
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gpio_toggle(GPIOC, GPIO8);
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}
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/* Set up timer to fire freq times per second */
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static void systick_setup(int freq)
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{
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systick_set_clocksource(STK_CSR_CLKSOURCE_AHB);
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/* clear counter so it starts right away */
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STK_CVR=0;
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systick_set_reload(rcc_core_frequency / freq);
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systick_counter_enable();
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systick_interrupt_enable();
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}
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/* set STM32 to clock by 48MHz from HSI oscillator */
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static void clock_setup(void)
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{
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rcc_clock_setup_in_hsi_out_48mhz();
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/* Enable clocks to the GPIO subsystems */
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rcc_periph_clock_enable(RCC_GPIOC);
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rcc_periph_clock_enable(RCC_GPIOA);
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}
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static void gpio_setup(void)
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{
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/* Select pin functions. PC8/PC9 are the two LEDs on the
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STM32F0DISCOVERY board. */
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gpio_mode_setup(GPIOC, GPIO_MODE_OUTPUT, GPIO_PUPD_NONE, GPIO8 | GPIO9);
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/* set GPIOA to AF 0 */
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gpio_mode_setup(GPIOA, GPIO_MODE_AF, GPIO_PUPD_NONE, GPIO8);
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}
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static void mco_setup(void)
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{
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/* Enable system clock output on pin PA8 (so it can be checked with a
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scope) */
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rcc_set_mco(RCC_CFGR_MCO_SYSCLK);
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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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mco_setup();
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/* setup systick to generate 2 LED flashes per second */
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systick_setup(8);
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/* Do nothing in main loop */
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while(1);
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}
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