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/******************************************************************************
* The MIT License
*
* Copyright (c) 2010 Perry Hung.
* Copyright (c) 2011 LeafLabs, LLC.
*
* Permission is hereby granted, free of charge, to any person
* obtaining a copy of this software and associated documentation
* files (the "Software"), to deal in the Software without
* restriction, including without limitation the rights to use, copy,
* modify, merge, publish, distribute, sublicense, and/or sell copies
* of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*****************************************************************************/
/**
* @file libmaple/usart.c
* @author Marti Bolivar <mbolivar@leaflabs.com>,
* Perry Hung <perry@leaflabs.com>
* @brief Portable USART routines
*/
#include <libmaple/usart.h>
/**
* @brief Initialize a serial port.
* @param dev Serial port to be initialized
*/
void usart_init(usart_dev *dev) {
rb_init(dev->rb, USART_RX_BUF_SIZE, dev->rx_buf);
rcc_clk_enable(dev->clk_id);
nvic_irq_enable(dev->irq_num);
}
/**
* @brief Enable a serial port.
*
* USART is enabled in single buffer transmission mode, multibuffer
* receiver mode, 8n1.
*
* Serial port must have a baud rate configured to work properly.
*
* @param dev Serial port to enable.
* @see usart_set_baud_rate()
*/
void usart_enable(usart_dev *dev) {
usart_reg_map *regs = dev->regs;
regs->CR1 = (USART_CR1_TE | USART_CR1_RE | USART_CR1_RXNEIE |
USART_CR1_M_8N1);
regs->CR1 |= USART_CR1_UE;
}
/**
* @brief Turn off a serial port.
* @param dev Serial port to be disabled
*/
void usart_disable(usart_dev *dev) {
/* FIXME this misbehaves (on F1) if you try to use PWM on TX afterwards */
usart_reg_map *regs = dev->regs;
/* TC bit must be high before disabling the USART */
while((regs->CR1 & USART_CR1_UE) && !(regs->SR & USART_SR_TC))
;
/* Disable UE */
regs->CR1 &= ~USART_CR1_UE;
/* Clean up buffer */
usart_reset_rx(dev);
}
/**
* @brief Nonblocking USART transmit
* @param dev Serial port to transmit over
* @param buf Buffer to transmit
* @param len Maximum number of bytes to transmit
* @return Number of bytes transmitted
*/
uint32 usart_tx(usart_dev *dev, const uint8 *buf, uint32 len) {
usart_reg_map *regs = dev->regs;
uint32 txed = 0;
while ((regs->SR & USART_SR_TXE) && (txed < len)) {
regs->DR = buf[txed++];
}
return txed;
}
/**
* @brief Nonblocking USART receive.
* @param dev Serial port to receive bytes from
* @param buf Buffer to store received bytes into
* @param len Maximum number of bytes to store
* @return Number of bytes received
*/
uint32 usart_rx(usart_dev *dev, uint8 *buf, uint32 len) {
uint32 rxed = 0;
while (usart_data_available(dev) && rxed < len) {
*buf++ = usart_getc(dev);
rxed++;
}
return rxed;
}
/**
* @brief Transmit an unsigned integer to the specified serial port in
* decimal format.
*
* This function blocks until the integer's digits have been
* completely transmitted.
*
* @param dev Serial port to send on
* @param val Number to print
*/
void usart_putudec(usart_dev *dev, uint32 val) {
char digits[12];
int i = 0;
do {
digits[i++] = val % 10 + '0';
val /= 10;
} while (val > 0);
while (--i >= 0) {
usart_putc(dev, digits[i]);
}
}
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