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authorStephen Caudle2011-11-02 22:50:49 -0400
committerStephen Caudle2011-11-02 22:50:49 -0400
commit3c9ba2ac2d51bb182ca85410021ab95b54ae4275 (patch)
tree5d6f47e81520f1e57ab04b17ab73ccbf629b9598 /examples
parent30b5c89726d4e30802d356bdf00acd8fab243af8 (diff)
Add usart example for STM32F4 discovery board
Diffstat (limited to 'examples')
-rw-r--r--examples/stm32/f4/stm32f4-discovery/usart/Makefile23
-rw-r--r--examples/stm32/f4/stm32f4-discovery/usart/README11
-rw-r--r--examples/stm32/f4/stm32f4-discovery/usart/usart.c87
-rw-r--r--examples/stm32/f4/stm32f4-discovery/usart/usart.ld32
4 files changed, 153 insertions, 0 deletions
diff --git a/examples/stm32/f4/stm32f4-discovery/usart/Makefile b/examples/stm32/f4/stm32f4-discovery/usart/Makefile
new file mode 100644
index 0000000..2c1e1b1
--- /dev/null
+++ b/examples/stm32/f4/stm32f4-discovery/usart/Makefile
@@ -0,0 +1,23 @@
+##
+## This file is part of the libopencm3 project.
+##
+## Copyright (C) 2009 Uwe Hermann <uwe@hermann-uwe.de>
+##
+## This program is free software: you can redistribute it and/or modify
+## it under the terms of the GNU General Public License as published by
+## the Free Software Foundation, either version 3 of the License, or
+## (at your option) any later version.
+##
+## This program 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 General Public License for more details.
+##
+## You should have received a copy of the GNU General Public License
+## along with this program. If not, see <http://www.gnu.org/licenses/>.
+##
+
+BINARY = usart
+
+include ../../Makefile.include
+
diff --git a/examples/stm32/f4/stm32f4-discovery/usart/README b/examples/stm32/f4/stm32f4-discovery/usart/README
new file mode 100644
index 0000000..168b364
--- /dev/null
+++ b/examples/stm32/f4/stm32f4-discovery/usart/README
@@ -0,0 +1,11 @@
+------------------------------------------------------------------------------
+README
+------------------------------------------------------------------------------
+
+This example program sends some characters on USART2 on the
+ST STM32F4DISCOVERY eval board.
+
+The terminal settings for the receiving device/PC are 38400 8n1.
+
+The sending is done in a blocking way in the code.
+
diff --git a/examples/stm32/f4/stm32f4-discovery/usart/usart.c b/examples/stm32/f4/stm32f4-discovery/usart/usart.c
new file mode 100644
index 0000000..c8ca2a3
--- /dev/null
+++ b/examples/stm32/f4/stm32f4-discovery/usart/usart.c
@@ -0,0 +1,87 @@
+/*
+ * This file is part of the libopencm3 project.
+ *
+ * Copyright (C) 2009 Uwe Hermann <uwe@hermann-uwe.de>
+ * Copyright (C) 2011 Stephen Caudle <scaudle@doceme.com>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <libopencm3/stm32/f4/rcc.h>
+#include <libopencm3/stm32/f4/gpio.h>
+#include <libopencm3/stm32/usart.h>
+
+void clock_setup(void)
+{
+ /* Enable GPIOD clock for LED & USARTs. */
+ rcc_peripheral_enable_clock(&RCC_AHB1ENR, RCC_AHB1ENR_IOPDEN);
+ rcc_peripheral_enable_clock(&RCC_AHB1ENR, RCC_AHB1ENR_IOPAEN);
+
+ /* Enable clocks for USART2. */
+ rcc_peripheral_enable_clock(&RCC_APB1ENR, RCC_APB1ENR_USART2EN);
+}
+
+void usart_setup(void)
+{
+ /* Setup USART2 parameters. */
+ usart_set_baudrate(USART2, 38400, rcc_ppre1_frequency);
+ usart_set_databits(USART2, 8);
+ usart_set_stopbits(USART2, USART_STOPBITS_1);
+ usart_set_mode(USART2, USART_MODE_TX);
+ usart_set_parity(USART2, USART_PARITY_NONE);
+ usart_set_flow_control(USART2, USART_FLOWCONTROL_NONE);
+
+ /* Finally enable the USART. */
+ usart_enable(USART2);
+}
+
+void gpio_setup(void)
+{
+ /* Setup GPIO pin GPIO12 on GPIO port D for LED. */
+ gpio_mode_setup(GPIOD, GPIO_MODE_OUTPUT,
+ GPIO_PUPD_NONE,
+ GPIO12);
+
+ /* Setup GPIO pins for USART2 transmit. */
+ gpio_mode_setup(GPIOA, GPIO_MODE_AF,
+ GPIO_PUPD_NONE,
+ GPIO2);
+
+ /* Setup USART2 TX pin as alternate function. */
+ gpio_set_af(GPIOA, GPIO_AF7, GPIO2);
+}
+
+int main(void)
+{
+ int i, j = 0, c = 0;
+
+ clock_setup();
+ gpio_setup();
+ usart_setup();
+
+ /* Blink the LED (PD12) on the board with every transmitted byte. */
+ while (1) {
+ gpio_toggle(GPIOD, GPIO12); /* LED on/off */
+ usart_send_blocking(USART2, c + '0'); /* USART2: Send byte. */
+ c = (c == 9) ? 0 : c + 1; /* Increment c. */
+ if ((j++ % 80) == 0) { /* Newline after line full. */
+ usart_send_blocking(USART2, '\r');
+ usart_send_blocking(USART2, '\n');
+ }
+ for (i = 0; i < 3000000; i++) /* Wait a bit. */
+ __asm__("NOP");
+ }
+
+ return 0;
+}
diff --git a/examples/stm32/f4/stm32f4-discovery/usart/usart.ld b/examples/stm32/f4/stm32f4-discovery/usart/usart.ld
new file mode 100644
index 0000000..1cb43c6
--- /dev/null
+++ b/examples/stm32/f4/stm32f4-discovery/usart/usart.ld
@@ -0,0 +1,32 @@
+/*
+ * This file is part of the libopencm3 project.
+ *
+ * Copyright (C) 2009 Uwe Hermann <uwe@hermann-uwe.de>
+ * Copyright (C) 2011 Stephen Caudle <scaudle@doceme.com>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+/* Linker script for ST STM32F4DISCOVERY (STM32F407VG, 1024K flash, 128K RAM). */
+
+/* Define memory regions. */
+MEMORY
+{
+ rom (rx) : ORIGIN = 0x08000000, LENGTH = 1024K
+ ram (rwx) : ORIGIN = 0x20000000, LENGTH = 128K
+}
+
+/* Include the common ld script. */
+INCLUDE libopencm3_stm32f4.ld
+