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/******************************************************************************
* The MIT License
*
* Copyright (c) 2010 Perry Hung.
*
* 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 usart.c
* @brief USART control routines
*/
#include "usart.h"
/*
* Devices
*/
static ring_buffer usart1_rb;
static usart_dev usart1 = {
.regs = USART1_BASE,
.rb = &usart1_rb,
.max_baud = 4500000UL,
.clk_id = RCC_USART1,
.irq_num = NVIC_USART1
};
usart_dev *USART1 = &usart1;
static ring_buffer usart2_rb;
static usart_dev usart2 = {
.regs = USART2_BASE,
.rb = &usart2_rb,
.max_baud = 2250000UL,
.clk_id = RCC_USART2,
.irq_num = NVIC_USART2
};
usart_dev *USART2 = &usart2;
static ring_buffer usart3_rb;
static usart_dev usart3 = {
.regs = USART3_BASE,
.rb = &usart3_rb,
.max_baud = 2250000UL,
.clk_id = RCC_USART3,
.irq_num = NVIC_USART3
};
usart_dev *USART3 = &usart3;
#ifdef STM32_HIGH_DENSITY
static ring_buffer uart4_rb;
static usart_dev uart4 = {
.regs = UART4_BASE,
.rb = &uart4_rb,
.max_baud = 2250000UL,
.clk_id = RCC_UART4,
.irq_num = NVIC_UART4
};
usart_dev *UART4 = &uart4;
static ring_buffer uart5_rb;
static usart_dev uart5 = {
.regs = UART5_BASE,
.rb = &uart5_rb,
.max_baud = 2250000UL,
.clk_id = RCC_UART5,
.irq_num = NVIC_UART5
};
usart_dev *UART5 = &uart5;
#endif
/**
* @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 Configure a serial port's baud rate.
*
* @param dev Serial port to be configured
* @param clock_speed Clock speed, in megahertz.
* @param baud Baud rate for transmit/receive.
*/
void usart_set_baud_rate(usart_dev *dev, uint32 clock_speed, uint32 baud) {
uint32 integer_part;
uint32 fractional_part;
uint32 tmp;
/* See ST RM0008 for the details on configuring the baud rate register */
integer_part = (25 * clock_speed) / (4 * baud);
tmp = (integer_part / 100) << 4;
fractional_part = integer_part - (100 * (tmp >> 4));
tmp |= (((fractional_part * 16) + 50) / 100) & ((uint8)0x0F);
dev->regs->BRR = (uint16)tmp;
}
/**
* @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;
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 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 Call a function on each USART.
* @param fn Function to call.
*/
void usart_foreach(void (*fn)(usart_dev *dev)) {
fn(USART1);
fn(USART2);
fn(USART3);
#ifdef STM32_HIGH_DENSITY
fn(UART4);
fn(UART5);
#endif
}
/**
* @brief Print a null-terminated string to the specified serial port.
* @param dev Serial port to send the string on
* @param str String to send
*/
void usart_putstr(usart_dev *dev, const char* str) {
char ch;
while ((ch = *(str++)) != '\0') {
usart_putc(dev, ch);
}
}
/**
* @brief Print an unsigned integer to the specified serial port.
*
* @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]);
}
}
/*
* Interrupt handlers.
*/
static inline void usart_irq(usart_dev *dev) {
#ifdef USART_SAFE_INSERT
/* Ignore new bytes if the user defines USART_SAFE_INSERT. */
rb_safe_insert(dev->rb, (uint8)dev->regs->DR);
#else
/* By default, push bytes around in the ring buffer. */
rb_push_insert(dev->rb, (uint8)dev->regs->DR);
#endif
}
void __irq_usart1(void) {
usart_irq(USART1);
}
void __irq_usart2(void) {
usart_irq(USART2);
}
void __irq_usart3(void) {
usart_irq(USART3);
}
#ifdef STM32_HIGH_DENSITY
void __irq_uart4(void) {
usart_irq(UART4);
}
void __irq_uart5(void) {
usart_irq(UART5);
}
#endif
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