ca926f00e0
This is not specifically an L1 example, but it lives beside the L1 "usart" example to show how easy it is to add semihosting support to existing code. Tested with the by now relatively old g-a-e 2012q4 release and OpenOcd 0.8.0-dev-00011-g70a2ffa (2013-05-14-19:41)
93 lines
2.8 KiB
C
93 lines
2.8 KiB
C
/*
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* This file is part of the libopencm3 project.
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*
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* Copyright (C) 2009 Uwe Hermann <uwe@hermann-uwe.de>
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* Copyright (C) 2012 Karl Palsson <karlp@tweak.net.au>
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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/stm32/usart.h>
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#include <stdio.h>
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/* For semihosting on newlib */
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extern void initialise_monitor_handles(void);
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static void clock_setup(void)
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{
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/* We are running on MSI after boot. */
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/* Enable GPIOD clock for LED & USARTs. */
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rcc_peripheral_enable_clock(&RCC_AHBENR, RCC_AHBENR_GPIOAEN);
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rcc_peripheral_enable_clock(&RCC_AHBENR, RCC_AHBENR_GPIOBEN);
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/* Enable clocks for USART2. */
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rcc_peripheral_enable_clock(&RCC_APB1ENR, RCC_APB1ENR_USART2EN);
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}
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static void usart_setup(void)
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{
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/* Setup USART2 parameters. */
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usart_set_baudrate(USART2, 115200);
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usart_set_databits(USART2, 8);
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usart_set_stopbits(USART2, USART_STOPBITS_1);
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usart_set_mode(USART2, USART_MODE_TX);
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usart_set_parity(USART2, USART_PARITY_NONE);
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usart_set_flow_control(USART2, USART_FLOWCONTROL_NONE);
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/* Finally enable the USART. */
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usart_enable(USART2);
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}
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static void gpio_setup(void)
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{
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/* Setup GPIO pin GPIO7 on GPIO port B for Green LED. */
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gpio_mode_setup(GPIOB, GPIO_MODE_OUTPUT, GPIO_PUPD_NONE, GPIO7);
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/* Setup GPIO pins for USART2 transmit. */
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gpio_mode_setup(GPIOA, GPIO_MODE_AF, GPIO_PUPD_NONE, GPIO2);
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/* Setup USART2 TX pin as alternate function. */
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gpio_set_af(GPIOA, GPIO_AF7, GPIO2);
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}
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int main(void)
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{
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int i, j = 0, c = 0;
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clock_setup();
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gpio_setup();
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usart_setup();
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#if defined(ENABLE_SEMIHOSTING) && (ENABLE_SEMIHOSTING)
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initialise_monitor_handles();
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#endif
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/* Blink the LED (PD12) on the board with every transmitted byte. */
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while (1) {
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gpio_toggle(GPIOB, GPIO7); /* LED on/off */
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usart_send_blocking(USART2, c + '0'); /* USART2: Send byte. */
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printf("Magic semihosting: %c\n", c + '0');
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c = (c == 9) ? 0 : c + 1; /* Increment c. */
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if ((j++ % 80) == 0) { /* Newline after line full. */
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usart_send_blocking(USART2, '\r');
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usart_send_blocking(USART2, '\n');
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}
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for (i = 0; i < 100000; 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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