86 lines
2.7 KiB
C
86 lines
2.7 KiB
C
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/* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU 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 program 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 General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*
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*/
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/* Copyright (c) 2016 King Kévin <kingkevin@cuvoodoo.info> */
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/* standard libraries */
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#include <stdint.h> // standard integer types
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#include <stdio.h> // standard I/O facilities
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#include <stdlib.h> // standard utilities
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#include <unistd.h> // standard streams
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#include <errno.h> // error number utilities
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/* STM32 (including CM3) libraries */
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#include <libopencm3/stm32/rcc.h> // real-time control clock library
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#include <libopencm3/stm32/gpio.h> // general purpose input output library
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#include <libopencm3/cm3/scb.h> // vector table definition
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/* own libraries */
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#include "main.h" // board definitions
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#include "usart.h" // USART utilities
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/* default output (i.e. for printf) */
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int _write(int file, char *ptr, int len)
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{
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int i;
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if (file == STDOUT_FILENO || file == STDERR_FILENO) {
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for (i = 0; i < len; i++) {
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if (ptr[i] == '\n') { // add carrier return before line feed. this is recommended for most UART terminals
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usart_putchar_nonblocking('\r'); // a second line feed doesn't break the display
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}
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usart_putchar_nonblocking(ptr[i]); // send byte over USART
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}
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return i;
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}
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errno = EIO;
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return -1;
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}
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static void clock_setup(void)
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{
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rcc_clock_setup_in_hse_8mhz_out_72mhz(); // use 8 MHz high speed external clock to generate 72 MHz internal clock
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rcc_periph_clock_enable(LED_RCC); //enable clock for LED
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}
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static void gpio_setup(void)
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{
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/* set LED pin to 'output push-pull' */
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gpio_set_mode(LED_PORT, GPIO_MODE_OUTPUT_2_MHZ, GPIO_CNF_OUTPUT_PUSHPULL, LED_PIN);
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}
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int main(void)
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{
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int i, c = 0;
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SCB_VTOR = (uint32_t) 0x08002000; // relocate vector table because of the bootloader
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clock_setup();
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gpio_setup();
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usart_setup();
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setbuf(stdout, NULL); // set standard out buffer to NULL to immediately print
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setbuf(stderr, NULL); // set standard error buffer to NULL to immediately print
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/* blink the LED with every transmitted character */
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while (1) {
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gpio_toggle(LED_PORT, LED_PIN); /* LED on/off */
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printf("%c",c+'0');
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c = (c == 9) ? 0 : c + 1; /* increment c */
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for (i = 0; i < 8000000; i++) /* wait a bit */
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__asm__("nop");
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}
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return 0;
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}
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