144 lines
4.3 KiB
C
144 lines
4.3 KiB
C
/** @addtogroup usart_file
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@author @htmlonly © @endhtmlonly 2009 Uwe Hermann <uwe@hermann-uwe.de>
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This library supports the USART/UART in the STM32F series
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of ARM Cortex Microcontrollers by ST Microelectronics.
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Devices can have up to 3 USARTs and 2 UARTs.
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*/
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/*
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* This file is part of the libopencm3 project.
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*
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* Copyright (C) 2009 Uwe Hermann <uwe@hermann-uwe.de>
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*
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* This library is free software: you can redistribute it and/or modify
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* it under the terms of the GNU Lesser General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public License
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* along with this library. If not, see <http://www.gnu.org/licenses/>.
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*/
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/**@{*/
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#include <libopencm3/stm32/usart.h>
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#include <libopencm3/stm32/rcc.h>
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/*---------------------------------------------------------------------------*/
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/** @brief USART Send a Data Word.
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@param[in] usart unsigned 32 bit. USART block register address base @ref
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usart_reg_base
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@param[in] data unsigned 16 bit.
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*/
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void usart_send(uint32_t usart, uint16_t data)
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{
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/* Send data. */
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USART_DR(usart) = (data & USART_DR_MASK);
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}
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/*---------------------------------------------------------------------------*/
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/** @brief USART Read a Received Data Word.
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If parity is enabled the MSB (bit 7 or 8 depending on the word length) is the
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parity bit.
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@param[in] usart unsigned 32 bit. USART block register address base @ref
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usart_reg_base
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@returns unsigned 16 bit data word.
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*/
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uint16_t usart_recv(uint32_t usart)
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{
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/* Receive data. */
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return USART_DR(usart) & USART_DR_MASK;
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}
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/*---------------------------------------------------------------------------*/
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/** @brief USART Wait for Transmit Data Buffer Empty
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Blocks until the transmit data buffer becomes empty and is ready to accept the
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next data word.
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@param[in] usart unsigned 32 bit. USART block register address base @ref
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usart_reg_base
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*/
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void usart_wait_send_ready(uint32_t usart)
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{
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/* Wait until the data has been transferred into the shift register. */
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while ((USART_SR(usart) & USART_SR_TXE) == 0);
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}
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/*---------------------------------------------------------------------------*/
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/** @brief USART Wait for Received Data Available
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Blocks until the receive data buffer holds a valid received data word.
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@param[in] usart unsigned 32 bit. USART block register address base @ref
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usart_reg_base
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*/
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void usart_wait_recv_ready(uint32_t usart)
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{
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/* Wait until the data is ready to be received. */
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while ((USART_SR(usart) & USART_SR_RXNE) == 0);
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}
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/*---------------------------------------------------------------------------*/
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/** @brief USART Read a Status Flag.
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@param[in] usart unsigned 32 bit. USART block register address base @ref
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usart_reg_base
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@param[in] flag Unsigned int32. Status register flag @ref usart_sr_flags.
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@returns boolean: flag set.
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*/
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bool usart_get_flag(uint32_t usart, uint32_t flag)
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{
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return ((USART_SR(usart) & flag) != 0);
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}
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/*---------------------------------------------------------------------------*/
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/** @brief USART Return Interrupt Source.
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Returns true if the specified interrupt flag (IDLE, RXNE, TC, TXE or OE) was
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set and the interrupt was enabled. If the specified flag is not an interrupt
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flag, the function returns false.
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@todo These are the most important interrupts likely to be used. Others
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relating to LIN break, and error conditions in multibuffer communication, need
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to be added for completeness.
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@param[in] usart unsigned 32 bit. USART block register address base @ref
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usart_reg_base
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@param[in] flag Unsigned int32. Status register flag @ref usart_sr_flags.
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@returns boolean: flag and interrupt enable both set.
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*/
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bool usart_get_interrupt_source(uint32_t usart, uint32_t flag)
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{
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uint32_t flag_set = (USART_SR(usart) & flag);
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/* IDLE, RXNE, TC, TXE interrupts */
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if ((flag >= USART_SR_IDLE) && (flag <= USART_SR_TXE)) {
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return ((flag_set & USART_CR1(usart)) != 0);
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/* Overrun error */
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} else if (flag == USART_SR_ORE) {
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return flag_set && (USART_CR3(usart) & USART_CR3_CTSIE);
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}
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return false;
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}
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/**@}*/
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