4d7a2ca271
Now that all families have support for calculating the clock of the uart, use that layer. Slightly slower for "old" families, but the only way to be correct for newer families. Reviewed-by: Karl Palsson <karlp@tweak.au>
418 lines
11 KiB
C
418 lines
11 KiB
C
/** @addtogroup usart_file USART peripheral API
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@ingroup peripheral_apis
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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 Set Baudrate.
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The baud rate is computed from the APB high-speed prescaler clock (for
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USART1/6) or the APB low-speed prescaler clock (for other USARTs). These values
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must be correctly set before calling this function (refer to the
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rcc_clock_setup-* functions in RCC).
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Note: For LPUART, baudrates over 2**24 (~16.7 Mbaud) may overflow
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the calculation and are therefore not supported by this function.
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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] baud unsigned 32 bit. Baud rate specified in Hz.
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*/
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void usart_set_baudrate(uint32_t usart, uint32_t baud)
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{
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uint32_t clock = rcc_get_usart_clk_freq(usart);
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/*
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* Yes it is as simple as that. The reference manual is
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* talking about fractional calculation but it seems to be only
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* marketing babble to sound awesome. It is nothing else but a
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* simple divider to generate the correct baudrate.
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*
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* Note: We round() the value rather than floor()ing it, for more
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* accurate divisor selection.
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*/
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#ifdef LPUART1
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if (usart == LPUART1) {
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USART_BRR(usart) = (clock / baud) * 256
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+ ((clock % baud) * 256 + baud / 2) / baud;
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return;
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}
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#endif
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USART_BRR(usart) = (clock + baud / 2) / baud;
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}
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/*---------------------------------------------------------------------------*/
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/** @brief USART Set Word Length.
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The word length is set to 8 or 9 bits. Note that the last bit will be a parity
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bit if parity is enabled, in which case the data length will be 7 or 8 bits
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respectively.
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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] bits unsigned 32 bit. Word length in bits 8 or 9.
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*/
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void usart_set_databits(uint32_t usart, uint32_t bits)
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{
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if (bits == 8) {
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USART_CR1(usart) &= ~USART_CR1_M; /* 8 data bits */
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} else {
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USART_CR1(usart) |= USART_CR1_M; /* 9 data bits */
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}
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}
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/*---------------------------------------------------------------------------*/
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/** @brief USART Set Stop Bit(s).
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The stop bits are specified as 0.5, 1, 1.5 or 2.
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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] stopbits unsigned 32 bit. Stop bits @ref usart_cr2_stopbits.
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*/
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void usart_set_stopbits(uint32_t usart, uint32_t stopbits)
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{
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uint32_t reg32;
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reg32 = USART_CR2(usart);
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reg32 = (reg32 & ~USART_CR2_STOPBITS_MASK) | stopbits;
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USART_CR2(usart) = reg32;
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}
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/*---------------------------------------------------------------------------*/
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/** @brief USART Set Parity.
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The parity bit can be selected as none, even or odd.
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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] parity unsigned 32 bit. Parity @ref usart_cr1_parity.
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*/
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void usart_set_parity(uint32_t usart, uint32_t parity)
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{
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uint32_t reg32;
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reg32 = USART_CR1(usart);
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reg32 = (reg32 & ~USART_PARITY_MASK) | parity;
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USART_CR1(usart) = reg32;
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}
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/*---------------------------------------------------------------------------*/
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/** @brief USART Set Rx/Tx Mode.
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The mode can be selected as Rx only, Tx only or Rx+Tx.
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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] mode unsigned 32 bit. Mode @ref usart_cr1_mode.
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*/
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void usart_set_mode(uint32_t usart, uint32_t mode)
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{
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uint32_t reg32;
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reg32 = USART_CR1(usart);
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reg32 = (reg32 & ~USART_MODE_MASK) | mode;
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USART_CR1(usart) = reg32;
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}
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/*---------------------------------------------------------------------------*/
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/** @brief USART Set Hardware Flow Control.
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The flow control bit can be selected as none, RTS, CTS or RTS+CTS.
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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] flowcontrol unsigned 32 bit. Flowcontrol @ref usart_cr3_flowcontrol.
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*/
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void usart_set_flow_control(uint32_t usart, uint32_t flowcontrol)
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{
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uint32_t reg32;
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reg32 = USART_CR3(usart);
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reg32 = (reg32 & ~USART_FLOWCONTROL_MASK) | flowcontrol;
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USART_CR3(usart) = reg32;
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}
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/*---------------------------------------------------------------------------*/
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/** @brief USART Enable.
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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_enable(uint32_t usart)
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{
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USART_CR1(usart) |= USART_CR1_UE;
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}
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/*---------------------------------------------------------------------------*/
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/** @brief USART Disable.
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At the end of the current frame, the USART is disabled to reduce power.
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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_disable(uint32_t usart)
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{
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USART_CR1(usart) &= ~USART_CR1_UE;
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}
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/*---------------------------------------------------------------------------*/
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/** @brief USART Send Data Word with Blocking
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Blocks until the transmit data buffer becomes empty then writes the next data
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word for transmission.
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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_blocking(uint32_t usart, uint16_t data)
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{
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usart_wait_send_ready(usart);
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usart_send(usart, data);
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}
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/*---------------------------------------------------------------------------*/
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/** @brief USART Read a Received Data Word with Blocking.
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Wait until a data word has been received then return the 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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@returns unsigned 16 bit data word.
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*/
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uint16_t usart_recv_blocking(uint32_t usart)
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{
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usart_wait_recv_ready(usart);
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return usart_recv(usart);
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}
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/*---------------------------------------------------------------------------*/
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/** @brief USART Receiver DMA Enable.
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DMA is available on:
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@li USART1 Rx DMA1 channel 5.
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@li USART2 Rx DMA1 channel 6.
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@li USART3 Rx DMA1 channel 3.
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@li UART4 Rx DMA2 channel 3.
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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_enable_rx_dma(uint32_t usart)
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{
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USART_CR3(usart) |= USART_CR3_DMAR;
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}
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/*---------------------------------------------------------------------------*/
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/** @brief USART Receiver DMA Disable.
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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_disable_rx_dma(uint32_t usart)
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{
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USART_CR3(usart) &= ~USART_CR3_DMAR;
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}
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/*---------------------------------------------------------------------------*/
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/** @brief USART Transmitter DMA Enable.
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DMA is available on:
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@li USART1 Tx DMA1 channel 4.
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@li USART2 Tx DMA1 channel 7.
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@li USART3 Tx DMA1 channel 2.
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@li UART4 Tx DMA2 channel 5.
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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_enable_tx_dma(uint32_t usart)
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{
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USART_CR3(usart) |= USART_CR3_DMAT;
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}
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/*---------------------------------------------------------------------------*/
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/** @brief USART Transmitter DMA Disable.
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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_disable_tx_dma(uint32_t usart)
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{
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USART_CR3(usart) &= ~USART_CR3_DMAT;
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}
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/*---------------------------------------------------------------------------*/
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/** @brief USART Receiver Interrupt Enable.
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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_enable_rx_interrupt(uint32_t usart)
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{
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USART_CR1(usart) |= USART_CR1_RXNEIE;
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}
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/*---------------------------------------------------------------------------*/
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/** @brief USART Receiver Interrupt Disable.
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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_disable_rx_interrupt(uint32_t usart)
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{
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USART_CR1(usart) &= ~USART_CR1_RXNEIE;
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}
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/*---------------------------------------------------------------------------*/
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/** @brief USART Transmitter Interrupt Enable.
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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_enable_tx_interrupt(uint32_t usart)
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{
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USART_CR1(usart) |= USART_CR1_TXEIE;
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}
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/*---------------------------------------------------------------------------*/
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/** @brief USART Transmitter Interrupt Disable.
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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_disable_tx_interrupt(uint32_t usart)
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{
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USART_CR1(usart) &= ~USART_CR1_TXEIE;
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}
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/*---------------------------------------------------------------------------*/
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/**
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* @brief USART Transmission Complete Interrupt Enable
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*
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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_enable_tx_complete_interrupt(uint32_t usart)
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{
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USART_CR1(usart) |= USART_CR1_TCIE;
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}
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/*---------------------------------------------------------------------------*/
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/**
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* @brief USART Transmission Complete Interrupt Disable
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*
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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_disable_tx_complete_interrupt(uint32_t usart)
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{
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USART_CR1(usart) &= ~USART_CR1_TCIE;
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}
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/** @brief USART Idle Interrupt Enable.
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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_enable_idle_interrupt(uint32_t usart)
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{
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USART_CR1(usart) |= USART_CR1_IDLEIE;
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}
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/*---------------------------------------------------------------------------*/
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/** @brief USART Idle Interrupt Disable.
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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_disable_idle_interrupt(uint32_t usart)
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{
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USART_CR1(usart) &= ~USART_CR1_IDLEIE;
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}
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/*---------------------------------------------------------------------------*/
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/** @brief USART Error Interrupt Enable.
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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_enable_error_interrupt(uint32_t usart)
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{
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USART_CR3(usart) |= USART_CR3_EIE;
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}
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/*---------------------------------------------------------------------------*/
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/** @brief USART Error Interrupt Disable.
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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_disable_error_interrupt(uint32_t usart)
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{
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USART_CR3(usart) &= ~USART_CR3_EIE;
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}
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/**@}*/
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