94 lines
2.5 KiB
C
94 lines
2.5 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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*
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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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/* This version derived from fancy blink */
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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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/*
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* Definitions for functions being abstracted out
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*/
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void msleep(uint32_t);
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void clock_setup(void);
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/* monotonically increasing number of milliseconds from reset
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* overflows every 49 days if you're wondering
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*/
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volatile uint32_t system_millis;
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/* Called when systick fires */
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void sys_tick_handler(void) {
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system_millis++;
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}
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/* sleep for delay milliseconds */
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void msleep(uint32_t delay) {
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uint32_t wake = system_millis + delay;
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while (wake > system_millis) ;
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}
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/*
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* clock_setup(void)
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*
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* This function sets up both the base board clock rate
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* and a 1khz "system tick" count. The SYSTICK counter is
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* a standard feature of the Cortex-M series.
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*/
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void clock_setup(void)
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{
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/* Base board frequency, set to 168Mhz */
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rcc_clock_setup_hse_3v3(&hse_8mhz_3v3[CLOCK_3V3_168MHZ]);
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/* clock rate / 168000 to get 1mS interrupt rate */
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systick_set_reload(168000);
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systick_set_clocksource(STK_CSR_CLKSOURCE_AHB);
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systick_counter_enable();
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/* this done last */
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systick_interrupt_enable();
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}
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int main(void)
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{
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/* Set up clock and systick */
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clock_setup();
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/* Enable GPIOD clock. */
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rcc_periph_clock_enable(RCC_GPIOG);
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/* Set GPIO13-14 (in GPIO port G) to 'output push-pull'. */
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gpio_mode_setup(GPIOG, GPIO_MODE_OUTPUT, GPIO_PUPD_NONE, GPIO13 | GPIO14);
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/* Set LED for alternating effect when toggling. */
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gpio_set(GPIOG, GPIO13);
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/* Blink the LEDs (PD12, PD13, PD14 and PD15) on the board. */
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while (1) {
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gpio_toggle(GPIOG, GPIO13 | GPIO14);
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/* Now sleep for 100ms which toggles at 10hz rate */
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msleep(100);
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}
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return 0;
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}
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