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authorKarl Palsson2012-10-22 21:29:42 +0000
committerKarl Palsson2012-11-07 21:50:27 +0000
commit25acaa58783b4d046acbe961cb62efe0b39ec981 (patch)
treedaedb9b86acd04f864c960d703483b37bd51ed94 /examples
parent2e5cfa39a522ac07518909a06276556ef864fb4c (diff)
Add usart support for L1.
Only tested with basic tx blocking, ie, the same example code as on F2/F4, but the description of the block is almost identical.
Diffstat (limited to 'examples')
-rw-r--r--examples/stm32/l1/stm32l-discovery/usart/Makefile25
-rw-r--r--examples/stm32/l1/stm32l-discovery/usart/README12
-rw-r--r--examples/stm32/l1/stm32l-discovery/usart/usart.c80
3 files changed, 117 insertions, 0 deletions
diff --git a/examples/stm32/l1/stm32l-discovery/usart/Makefile b/examples/stm32/l1/stm32l-discovery/usart/Makefile
new file mode 100644
index 0000000..ac088fe
--- /dev/null
+++ b/examples/stm32/l1/stm32l-discovery/usart/Makefile
@@ -0,0 +1,25 @@
+##
+## 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
+
+LDSCRIPT = ../../../../../lib/stm32/l1/stm32l15xxb.ld
+
+include ../../Makefile.include
+
diff --git a/examples/stm32/l1/stm32l-discovery/usart/README b/examples/stm32/l1/stm32l-discovery/usart/README
new file mode 100644
index 0000000..dcbc5d9
--- /dev/null
+++ b/examples/stm32/l1/stm32l-discovery/usart/README
@@ -0,0 +1,12 @@
+------------------------------------------------------------------------------
+README
+------------------------------------------------------------------------------
+
+This example program sends some characters on USART2 on the
+ST STM32L DISCOVERY eval board. (USART2 TX on PA2)
+
+The terminal settings for the receiving device/PC are 38400 8n1.
+
+The sending is done in a blocking way in the code, see the usart_irq example
+for a more elaborate USART example.
+
diff --git a/examples/stm32/l1/stm32l-discovery/usart/usart.c b/examples/stm32/l1/stm32l-discovery/usart/usart.c
new file mode 100644
index 0000000..3335ca8
--- /dev/null
+++ b/examples/stm32/l1/stm32l-discovery/usart/usart.c
@@ -0,0 +1,80 @@
+/*
+ * This file is part of the libopencm3 project.
+ *
+ * Copyright (C) 2009 Uwe Hermann <uwe@hermann-uwe.de>
+ * Copyright (C) 2012 Karl Palsson <karlp@tweak.net.au>
+ *
+ * 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/l1/rcc.h>
+#include <libopencm3/stm32/l1/gpio.h>
+#include <libopencm3/stm32/usart.h>
+
+void clock_setup(void) {
+ /* We are running on MSI after boot. */
+ /* Enable GPIOD clock for LED & USARTs. */
+ rcc_peripheral_enable_clock(&RCC_AHBENR, RCC_AHBENR_GPIOAEN);
+ rcc_peripheral_enable_clock(&RCC_AHBENR, RCC_AHBENR_GPIOBEN);
+
+ /* 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);
+ 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 GPIO7 on GPIO port B for Green LED. */
+ gpio_mode_setup(GPIOB, GPIO_MODE_OUTPUT, GPIO_PUPD_NONE, GPIO7);
+
+ /* 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(GPIOB, GPIO7); /* 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 < 100000; i++) /* Wait a bit. */
+ __asm__("NOP");
+ }
+
+ return 0;
+}