From 8b062bb659a696e5d9ff910bc7d7c986c9b1151d Mon Sep 17 00:00:00 2001 From: Piotr Esden-Tempski Date: Mon, 28 Jan 2013 18:26:46 -0800 Subject: Added IRQ USART example for the f4 discovery board. --- .../stm32/f4/stm32f4-discovery/usart_irq/Makefile | 25 +++++ .../stm32/f4/stm32f4-discovery/usart_irq/README | 14 +++ .../f4/stm32f4-discovery/usart_irq/usart_irq.c | 115 +++++++++++++++++++++ 3 files changed, 154 insertions(+) create mode 100644 examples/stm32/f4/stm32f4-discovery/usart_irq/Makefile create mode 100644 examples/stm32/f4/stm32f4-discovery/usart_irq/README create mode 100644 examples/stm32/f4/stm32f4-discovery/usart_irq/usart_irq.c (limited to 'examples') diff --git a/examples/stm32/f4/stm32f4-discovery/usart_irq/Makefile b/examples/stm32/f4/stm32f4-discovery/usart_irq/Makefile new file mode 100644 index 0000000..b7bbd14 --- /dev/null +++ b/examples/stm32/f4/stm32f4-discovery/usart_irq/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_irq + +LDSCRIPT = ../stm32f4-discovery.ld + +include ../../Makefile.include + diff --git a/examples/stm32/f4/stm32f4-discovery/usart_irq/README b/examples/stm32/f4/stm32f4-discovery/usart_irq/README new file mode 100644 index 0000000..ac859a9 --- /dev/null +++ b/examples/stm32/f4/stm32f4-discovery/usart_irq/README @@ -0,0 +1,14 @@ +------------------------------------------------------------------------------ +README +------------------------------------------------------------------------------ + +This example program echoes data sent in on USART2 on the +ST STM32F4DISCOVERY eval board. Uses interrupts for that purpose. + +Connect your TTL RX device line to PA2 on the discovery board. +Connect your TTL TX device line to PA3 on the discovery 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_irq/usart_irq.c b/examples/stm32/f4/stm32f4-discovery/usart_irq/usart_irq.c new file mode 100644 index 0000000..8e7aa7f --- /dev/null +++ b/examples/stm32/f4/stm32f4-discovery/usart_irq/usart_irq.c @@ -0,0 +1,115 @@ +/* + * This file is part of the libopencm3 project. + * + * Copyright (C) 2009 Uwe Hermann + * Copyright (C) 2011 Stephen Caudle + * Copyright (C) 2013 Piotr Esden-Tempski + * + * 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 +#include + +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) +{ + /* Enable the USART2 interrupt. */ + nvic_enable_irq(NVIC_USART2_IRQ); + + /* Setup GPIO pins for USART2 transmit. */ + gpio_mode_setup(GPIOA, GPIO_MODE_AF, GPIO_PUPD_NONE, GPIO2); + + /* Setup GPIO pins for USART2 receive. */ + gpio_mode_setup(GPIOA, GPIO_MODE_AF, GPIO_PUPD_NONE, GPIO3); + gpio_set_output_options(GPIOA, GPIO_OTYPE_OD, GPIO_OSPEED_25MHZ, GPIO3); + + /* Setup USART2 TX and RX pin as alternate function. */ + gpio_set_af(GPIOA, GPIO_AF7, GPIO2); + gpio_set_af(GPIOA, GPIO_AF7, GPIO3); + + /* 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_RX); + usart_set_parity(USART2, USART_PARITY_NONE); + usart_set_flow_control(USART2, USART_FLOWCONTROL_NONE); + + /* Enable USART2 Receive interrupt. */ + usart_enable_rx_interrupt(USART2); + + /* 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); +} + +int main(void) +{ + clock_setup(); + gpio_setup(); + usart_setup(); + + while (1) { + __asm__("NOP"); + } + + return 0; +} + +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(GPIOD, GPIO12); + + /* Retrieve the data from the peripheral. */ + data = usart_recv(USART2); + + /* Enable transmit interrupt so it sends back the data. */ + usart_enable_tx_interrupt(USART2); + } + + /* Check if we were called because of TXE. */ + if (((USART_CR1(USART2) & USART_CR1_TXEIE) != 0) && + ((USART_SR(USART2) & USART_SR_TXE) != 0)) { + + /* Put data into the transmit register. */ + usart_send(USART2, data); + + /* Disable the TXE interrupt as we don't need it anymore. */ + usart_disable_tx_interrupt(USART2); + } +} -- cgit v1.2.3