From 25acaa58783b4d046acbe961cb62efe0b39ec981 Mon Sep 17 00:00:00 2001 From: Karl Palsson Date: Mon, 22 Oct 2012 21:29:42 +0000 Subject: 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. --- examples/stm32/l1/stm32l-discovery/usart/Makefile | 25 +++++++ examples/stm32/l1/stm32l-discovery/usart/README | 12 ++++ examples/stm32/l1/stm32l-discovery/usart/usart.c | 80 +++++++++++++++++++++++ 3 files changed, 117 insertions(+) create mode 100644 examples/stm32/l1/stm32l-discovery/usart/Makefile create mode 100644 examples/stm32/l1/stm32l-discovery/usart/README create mode 100644 examples/stm32/l1/stm32l-discovery/usart/usart.c (limited to 'examples/stm32') 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 +## +## 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 . +## + +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 + * Copyright (C) 2012 Karl Palsson + * + * 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 . + */ + +#include +#include +#include + +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; +} -- cgit v1.2.3