usart_common_all.c

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/** @addtogroup usart_file USART peripheral API
@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 Set Baudrate.
 
The baud rate is computed from the APB high-speed prescaler clock (for
USART1/6) or the APB low-speed prescaler clock (for other USARTs). These values
must be correctly set before calling this function (refer to the
rcc_clock_setup-* functions in RCC).
 
Note: For LPUART, baudrates over 2**24 (~16.7 Mbaud) may overflow
the calculation and are therefore not supported by this function.
 
@param[in] usart unsigned 32 bit. USART block register address base @ref
usart_reg_base
@param[in] baud unsigned 32 bit. Baud rate specified in Hz.
*/
 
void usart_set_baudrate(uint32_t usart, uint32_t baud)
{
        uint32_t clock = rcc_get_usart_clk_freq(usart);
 
        /*
         * Yes it is as simple as that. The reference manual is
         * talking about fractional calculation but it seems to be only
         * marketing babble to sound awesome. It is nothing else but a
         * simple divider to generate the correct baudrate.
         *
         * Note: We round() the value rather than floor()ing it, for more
         * accurate divisor selection.
         */
#ifdef LPUART1
        if (usart == LPUART1) {
                USART_BRR(usart) = (clock / baud) * 256
                        + ((clock % baud) * 256 + baud / 2) / baud;
                return;
        }
#endif
 
        USART_BRR(usart) = (clock + baud / 2) / baud;
}
 
/*---------------------------------------------------------------------------*/
/** @brief USART Set Word Length.
 
The word length is set to 8 or 9 bits. Note that the last bit will be a parity
bit if parity is enabled, in which case the data length will be 7 or 8 bits
respectively.
 
@param[in] usart unsigned 32 bit. USART block register address base @ref
usart_reg_base
@param[in] bits unsigned 32 bit. Word length in bits 8 or 9.
*/
 
void usart_set_databits(uint32_t usart, uint32_t bits)
{
        if (bits == 8) {
                USART_CR1(usart) &= ~USART_CR1_M; /* 8 data bits */
        } else {
                USART_CR1(usart) |= USART_CR1_M;  /* 9 data bits */
        }
}
 
/*---------------------------------------------------------------------------*/
/** @brief USART Set Stop Bit(s).
 
The stop bits are specified as 0.5, 1, 1.5 or 2.
 
@param[in] usart unsigned 32 bit. USART block register address base @ref
usart_reg_base
@param[in] stopbits unsigned 32 bit. Stop bits @ref usart_cr2_stopbits.
*/
 
void usart_set_stopbits(uint32_t usart, uint32_t stopbits)
{
        uint32_t reg32;
 
        reg32 = USART_CR2(usart);
        reg32 = (reg32 & ~USART_CR2_STOPBITS_MASK) | stopbits;
        USART_CR2(usart) = reg32;
}
 
/*---------------------------------------------------------------------------*/
/** @brief USART Set Parity.
 
The parity bit can be selected as none, even or odd.
 
@param[in] usart unsigned 32 bit. USART block register address base @ref
usart_reg_base
@param[in] parity unsigned 32 bit. Parity @ref usart_cr1_parity.
*/
 
void usart_set_parity(uint32_t usart, uint32_t parity)
{
        uint32_t reg32;
 
        reg32 = USART_CR1(usart);
        reg32 = (reg32 & ~USART_PARITY_MASK) | parity;
        USART_CR1(usart) = reg32;
}
 
/*---------------------------------------------------------------------------*/
/** @brief USART Set Rx/Tx Mode.
 
The mode can be selected as Rx only, Tx only or Rx+Tx.
 
@param[in] usart unsigned 32 bit. USART block register address base @ref
usart_reg_base
@param[in] mode unsigned 32 bit. Mode @ref usart_cr1_mode.
*/
 
void usart_set_mode(uint32_t usart, uint32_t mode)
{
        uint32_t reg32;
 
        reg32 = USART_CR1(usart);
        reg32 = (reg32 & ~USART_MODE_MASK) | mode;
        USART_CR1(usart) = reg32;
}
 
/*---------------------------------------------------------------------------*/
/** @brief USART Set Hardware Flow Control.
 
The flow control bit can be selected as none, RTS, CTS or RTS+CTS.
 
@param[in] usart unsigned 32 bit. USART block register address base @ref
usart_reg_base
@param[in] flowcontrol unsigned 32 bit. Flowcontrol @ref usart_cr3_flowcontrol.
*/
 
void usart_set_flow_control(uint32_t usart, uint32_t flowcontrol)
{
        uint32_t reg32;
 
        reg32 = USART_CR3(usart);
        reg32 = (reg32 & ~USART_FLOWCONTROL_MASK) | flowcontrol;
        USART_CR3(usart) = reg32;
}
 
/*---------------------------------------------------------------------------*/
/** @brief USART Enable.
 
@param[in] usart unsigned 32 bit. USART block register address base @ref
usart_reg_base
*/
 
void usart_enable(uint32_t usart)
{
        USART_CR1(usart) |= USART_CR1_UE;
}
 
/*---------------------------------------------------------------------------*/
/** @brief USART Disable.
 
At the end of the current frame, the USART is disabled to reduce power.
 
@param[in] usart unsigned 32 bit. USART block register address base @ref
usart_reg_base
*/
 
void usart_disable(uint32_t usart)
{
        USART_CR1(usart) &= ~USART_CR1_UE;
}
 
/*---------------------------------------------------------------------------*/
/** @brief USART Send Data Word with Blocking
 
Blocks until the transmit data buffer becomes empty then writes the next data
word for transmission.
 
@param[in] usart unsigned 32 bit. USART block register address base @ref
usart_reg_base
@param[in] data unsigned 16 bit.
*/
 
void usart_send_blocking(uint32_t usart, uint16_t data)
{
        usart_wait_send_ready(usart);
        usart_send(usart, data);
}
 
/*---------------------------------------------------------------------------*/
/** @brief USART Read a Received Data Word with Blocking.
 
Wait until a data word has been received then return the word.
 
@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_blocking(uint32_t usart)
{
        usart_wait_recv_ready(usart);
 
        return usart_recv(usart);
}
 
/*---------------------------------------------------------------------------*/
/** @brief USART Receiver DMA Enable.
 
DMA is available on:
@li USART1 Rx DMA1 channel 5.
@li USART2 Rx DMA1 channel 6.
@li USART3 Rx DMA1 channel 3.
@li UART4 Rx DMA2 channel 3.
 
@param[in] usart unsigned 32 bit. USART block register address base @ref
usart_reg_base
*/
 
void usart_enable_rx_dma(uint32_t usart)
{
        USART_CR3(usart) |= USART_CR3_DMAR;
}
 
/*---------------------------------------------------------------------------*/
/** @brief USART Receiver DMA Disable.
 
@param[in] usart unsigned 32 bit. USART block register address base @ref
usart_reg_base
*/
 
void usart_disable_rx_dma(uint32_t usart)
{
        USART_CR3(usart) &= ~USART_CR3_DMAR;
}
 
/*---------------------------------------------------------------------------*/
/** @brief USART Transmitter DMA Enable.
 
DMA is available on:
@li USART1 Tx DMA1 channel 4.
@li USART2 Tx DMA1 channel 7.
@li USART3 Tx DMA1 channel 2.
@li UART4 Tx DMA2 channel 5.
 
@param[in] usart unsigned 32 bit. USART block register address base @ref
usart_reg_base
*/
 
void usart_enable_tx_dma(uint32_t usart)
{
        USART_CR3(usart) |= USART_CR3_DMAT;
}
 
/*---------------------------------------------------------------------------*/
/** @brief USART Transmitter DMA Disable.
 
@param[in] usart unsigned 32 bit. USART block register address base @ref
usart_reg_base
*/
 
void usart_disable_tx_dma(uint32_t usart)
{
        USART_CR3(usart) &= ~USART_CR3_DMAT;
}
 
/*---------------------------------------------------------------------------*/
/** @brief USART Receiver Interrupt Enable.
 
@param[in] usart unsigned 32 bit. USART block register address base @ref
usart_reg_base
*/
 
void usart_enable_rx_interrupt(uint32_t usart)
{
        USART_CR1(usart) |= USART_CR1_RXNEIE;
}
 
 
/*---------------------------------------------------------------------------*/
/** @brief USART Receiver Interrupt Disable.
 
@param[in] usart unsigned 32 bit. USART block register address base @ref
usart_reg_base
*/
 
void usart_disable_rx_interrupt(uint32_t usart)
{
        USART_CR1(usart) &= ~USART_CR1_RXNEIE;
}
 
/*---------------------------------------------------------------------------*/
/** @brief USART Transmitter Interrupt Enable.
 
@param[in] usart unsigned 32 bit. USART block register address base @ref
usart_reg_base
*/
 
void usart_enable_tx_interrupt(uint32_t usart)
{
        USART_CR1(usart) |= USART_CR1_TXEIE;
}
 
/*---------------------------------------------------------------------------*/
/** @brief USART Transmitter Interrupt Disable.
 
@param[in] usart unsigned 32 bit. USART block register address base @ref
usart_reg_base
*/
 
void usart_disable_tx_interrupt(uint32_t usart)
{
        USART_CR1(usart) &= ~USART_CR1_TXEIE;
}
 
/*---------------------------------------------------------------------------*/
/**
 * @brief USART Transmission Complete Interrupt Enable
 * 
 * @param[in] usart unsigned 32 bit. USART block register address base @ref
usart_reg_base
 */
 
void usart_enable_tx_complete_interrupt(uint32_t usart)
{
        USART_CR1(usart) |= USART_CR1_TCIE;
}
 
/*---------------------------------------------------------------------------*/
/**
 * @brief USART Transmission Complete Interrupt Disable
 * 
 * @param[in] usart unsigned 32 bit. USART block register address base @ref
usart_reg_base
 */
 
void usart_disable_tx_complete_interrupt(uint32_t usart)
{
        USART_CR1(usart) &= ~USART_CR1_TCIE;
}
 
/** @brief USART Idle Interrupt Enable.
 
@param[in] usart unsigned 32 bit. USART block register address base @ref
usart_reg_base
*/
 
void usart_enable_idle_interrupt(uint32_t usart)
{
        USART_CR1(usart) |= USART_CR1_IDLEIE;
}
 
/*---------------------------------------------------------------------------*/
/** @brief USART Idle Interrupt Disable.
 
@param[in] usart unsigned 32 bit. USART block register address base @ref
usart_reg_base
*/
 
void usart_disable_idle_interrupt(uint32_t usart)
{
        USART_CR1(usart) &= ~USART_CR1_IDLEIE;
}
 
/*---------------------------------------------------------------------------*/
/** @brief USART Error Interrupt Enable.
 
@param[in] usart unsigned 32 bit. USART block register address base @ref
usart_reg_base
*/
 
void usart_enable_error_interrupt(uint32_t usart)
{
        USART_CR3(usart) |= USART_CR3_EIE;
}
 
/*---------------------------------------------------------------------------*/
/** @brief USART Error Interrupt Disable.
 
@param[in] usart unsigned 32 bit. USART block register address base @ref
usart_reg_base
*/
 
void usart_disable_error_interrupt(uint32_t usart)
{
        USART_CR3(usart) &= ~USART_CR3_EIE;
}
 
/**@}*/