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/** @addtogroup usart_file
@ingroup peripheral_apis
@author @htmlonly &copy; @endhtmlonly 2009 Uwe Hermann <uwe@hermann-uwe.de>
This library supports the USART/UART in the STM32F series
of ARM Cortex Microcontrollers by ST Microelectronics.
Devices can have up to 3 USARTs and 2 UARTs.
*/
/*
* 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/>.
*/
/**@{*/
#include <libopencm3/stm32/usart.h>
#include <libopencm3/stm32/rcc.h>
/*---------------------------------------------------------------------------*/
/** @brief USART Send a Data Word.
@param[in] usart unsigned 32 bit. USART block register address base @ref
usart_reg_base
@param[in] data unsigned 16 bit.
*/
void usart_send(uint32_t usart, uint16_t data)
{
/* Send data. */
USART_DR(usart) = (data & USART_DR_MASK);
}
/*---------------------------------------------------------------------------*/
/** @brief USART Read a Received Data Word.
If parity is enabled the MSB (bit 7 or 8 depending on the word length) is the
parity bit.
@param[in] usart unsigned 32 bit. USART block register address base @ref
usart_reg_base
@returns unsigned 16 bit data word.
*/
uint16_t usart_recv(uint32_t usart)
{
/* Receive data. */
return USART_DR(usart) & USART_DR_MASK;
}
/*---------------------------------------------------------------------------*/
/** @brief USART Wait for Transmit Data Buffer Empty
Blocks until the transmit data buffer becomes empty and is ready to accept the
next data word.
@param[in] usart unsigned 32 bit. USART block register address base @ref
usart_reg_base
*/
void usart_wait_send_ready(uint32_t usart)
{
/* Wait until the data has been transferred into the shift register. */
while ((USART_SR(usart) & USART_SR_TXE) == 0);
}
/*---------------------------------------------------------------------------*/
/** @brief USART Wait for Received Data Available
Blocks until the receive data buffer holds a valid received data word.
@param[in] usart unsigned 32 bit. USART block register address base @ref
usart_reg_base
*/
void usart_wait_recv_ready(uint32_t usart)
{
/* Wait until the data is ready to be received. */
while ((USART_SR(usart) & USART_SR_RXNE) == 0);
}
/*---------------------------------------------------------------------------*/
/** @brief USART Read a Status Flag.
@param[in] usart unsigned 32 bit. USART block register address base @ref
usart_reg_base
@param[in] flag Unsigned int32. Status register flag @ref usart_sr_flags.
@returns boolean: flag set.
*/
bool usart_get_flag(uint32_t usart, uint32_t flag)
{
return ((USART_SR(usart) & flag) != 0);
}
/**@}*/