Added usart irq example for lisa/m 2.0

examples/stm32/f1/lisa-m-2/usart_irq/Makefile

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+##
+## This file is part of the libopencm3 project.
+##
+## Copyright (C) 2009 Uwe Hermann <uwe@hermann-uwe.de>
+##
+## This library is free software: you can redistribute it and/or modify
+## it under the terms of the GNU Lesser General Public License as published by
+## the Free Software Foundation, either version 3 of the License, or
+## (at your option) any later version.
+##
+## This library is distributed in the hope that it will be useful,
+## but WITHOUT ANY WARRANTY; without even the implied warranty of
+## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+## GNU Lesser General Public License for more details.
+##
+## You should have received a copy of the GNU Lesser General Public License
+## along with this library.  If not, see <http://www.gnu.org/licenses/>.
+##
+
+BINARY = usart_irq
+
+LDSCRIPT = ../lisa-m.ld
+
+include ../../Makefile.include
+

examples/stm32/f1/lisa-m-2/usart_irq/usart_irq.c

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+/*
+ * This file is part of the libopencm3 project.
+ *
+ * Copyright (C) 2009 Uwe Hermann <uwe@hermann-uwe.de>
+ *
+ * This library is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this library.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <libopencm3/stm32/f1/rcc.h>
+#include <libopencm3/stm32/f1/gpio.h>
+#include <libopencm3/stm32/usart.h>
+#include <libopencm3/stm32/nvic.h>
+
+void clock_setup(void)
+{
+	rcc_clock_setup_in_hse_12mhz_out_72mhz();
+
+	/* Enable GPIOA clock (for LED GPIOs). */
+	rcc_peripheral_enable_clock(&RCC_APB2ENR, RCC_APB2ENR_IOPAEN | RCC_APB2ENR_IOPCEN);
+
+	/* Enable clocks for GPIO port A (for GPIO_USART2_TX) and USART2. */
+	rcc_peripheral_enable_clock(&RCC_APB2ENR, RCC_APB2ENR_IOPAEN |
+				    RCC_APB2ENR_AFIOEN);
+
+	rcc_peripheral_enable_clock(&RCC_APB1ENR, RCC_APB1ENR_USART2EN);
+}
+
+void usart_setup(void)
+{
+	/* Enable the USART2 interrupt. */
+	nvic_enable_irq(NVIC_USART2_IRQ);
+
+	/* Setup GPIO pin GPIO_USART2_TX on GPIO port A for transmit. */
+	gpio_set_mode(GPIO_BANK_USART2_TX, GPIO_MODE_OUTPUT_50_MHZ,
+		      GPIO_CNF_OUTPUT_ALTFN_PUSHPULL, GPIO_USART2_TX);
+
+	/* Setup GPIO pin GPIO_USART2_RX on GPIO port A for receive. */
+	gpio_set_mode(GPIO_BANK_USART2_RX, GPIO_MODE_INPUT,
+		      GPIO_CNF_INPUT_FLOAT, GPIO_USART2_RX);
+
+	/* Setup UART parameters. */
+	usart_set_baudrate(USART2, 230400);
+	usart_set_databits(USART2, 8);
+	usart_set_stopbits(USART2, USART_STOPBITS_1);
+	usart_set_parity(USART2, USART_PARITY_NONE);
+	usart_set_flow_control(USART2, USART_FLOWCONTROL_NONE);
+	usart_set_mode(USART2, USART_MODE_TX_RX);
+
+	/* Enable USART2 Receive interrupt. */
+	USART_CR1(USART2) |= USART_CR1_RXNEIE;
+
+	/* Finally enable the USART. */
+	usart_enable(USART2);
+}
+
+void gpio_setup(void)
+{
+	gpio_set(GPIOA, GPIO8);
+
+	/* Setup GPIO8 (in GPIO port A) for LED use. */
+	gpio_set_mode(GPIOA, GPIO_MODE_OUTPUT_50_MHZ,
+		      GPIO_CNF_OUTPUT_PUSHPULL, GPIO8);
+	
+	gpio_set(GPIOC, GPIO15);
+
+	/* Setup GPIO15 (in GPIO port C) for LED use. */
+	gpio_set_mode(GPIOC, GPIO_MODE_OUTPUT_50_MHZ,
+		      GPIO_CNF_OUTPUT_PUSHPULL, GPIO15);
+}
+
+void usart2_isr(void)
+{
+	static u8 data = 'A';
+
+	/* Check if we were called because of RXNE. */
+	if (((USART_CR1(USART2) & USART_CR1_RXNEIE) != 0) &&
+	    ((USART_SR(USART2) & USART_SR_RXNE) != 0)) {
+
+		/* Indicate that we got data. */
+		gpio_toggle(GPIOA, GPIO8);
+
+		/* Retrieve the data from the peripheral. */
+		data = usart_recv(USART2);
+
+		/* Enable transmit interrupt so it sends back the data. */
+		USART_CR1(USART2) |= USART_CR1_TXEIE;
+	}
+
+	/* Check if we were called because of TXE. */
+	if (((USART_CR1(USART2) & USART_CR1_TXEIE) != 0) &&
+	    ((USART_SR(USART2) & USART_SR_TXE) != 0)) {
+
+		/* Indicate that we are sending out data. */
+		gpio_toggle(GPIOC, GPIO15);
+
+		/* Put data into the transmit register. */
+		usart_send(USART2, data);
+
+		/* Disable the TXE interrupt as we don't need it anymore. */
+		USART_CR1(USART2) &= ~USART_CR1_TXEIE;
+	}
+}
+
+int main(void)
+{
+	clock_setup();
+	gpio_setup();
+	usart_setup();
+
+	/* Wait forever and do nothing. */
+	while (1)
+		__asm__("nop");
+
+	return 0;
+}