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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 "libmaple.h"
#include "rcc.h"
#include "nvic.h"
#include "usart.h"
#define USART1_BASE 0x40013800
#define USART2_BASE 0x40004400
#define USART3_BASE 0x40004800
#define USART_UE BIT(13)
#define USART_M BIT(12)
#define USART_TE BIT(3)
#define USART_RE BIT(2)
#define USART_RXNEIE BIT(5) // read data register not empty interrupt enable
#define USART_TC BIT(6)
/* usart descriptor table */
struct usart_dev usart_dev_table[] = {
[USART1] = {
.base = (usart_port*)USART1_BASE,
.rcc_dev_num = RCC_USART1,
.nvic_dev_num = NVIC_USART1
},
[USART2] = {
.base = (usart_port*)USART2_BASE,
.rcc_dev_num = RCC_USART2,
.nvic_dev_num = NVIC_USART2
},
[USART3] = {
.base = (usart_port*)USART3_BASE,
.rcc_dev_num = RCC_USART3,
.nvic_dev_num = NVIC_USART3
},
};
/* usart interrupt handlers */
void USART1_IRQHandler(void) {
rb_insert(&(usart_dev_table[USART1].rb), (uint8)(((usart_port*)(USART1_BASE))->DR));
}
void USART2_IRQHandler(void) {
rb_insert(&(usart_dev_table[USART2].rb), (uint8)(((usart_port*)(USART2_BASE))->DR));
}
void USART3_IRQHandler(void) {
rb_insert(&usart_dev_table[USART3].rb, (uint8)(((usart_port*)(USART3_BASE))->DR));
}
/**
* @brief Enable a USART in single buffer transmission mode, multibuffer
* receiver mode.
* @param usart_num USART to be initialized
* @param baud Baud rate to be set at
*/
void usart_init(uint8 usart_num, uint32 baud) {
usart_port *port;
ring_buffer *ring_buf;
uint32 clk_speed;
uint32 integer_part;
uint32 fractional_part;
uint32 tmp;
port = usart_dev_table[usart_num].base;
rcc_clk_enable(usart_dev_table[usart_num].rcc_dev_num);
nvic_irq_enable(usart_dev_table[usart_num].nvic_dev_num);
/* usart1 is mad fast */
clk_speed = (usart_num == USART1) ? 72000000UL : 36000000UL;
/* Initialize rx ring buffer */
rb_init(&usart_dev_table[usart_num].rb,
sizeof (usart_dev_table[usart_num].rx_buf),
usart_dev_table[usart_num].rx_buf);
/* Set baud rate */
integer_part = ((25 * clk_speed) / (4 * baud));
tmp = (integer_part / 100) << 4;
fractional_part = integer_part - (100 * (tmp >> 4));
tmp |= (((fractional_part * 16) + 50) / 100) & ((uint8)0x0F);
port->BRR = (uint16)tmp;
port->CR1 = USART_TE | // transmitter enable
USART_RE | // receiver enable
USART_RXNEIE; // receive interrupt enable
/* Enable the USART and set mode to 8n1 */
port->CR1 |= USART_UE;
}
/**
* @brief Turn off a USART.
* @param USART to be disabled
*/
void usart_disable(uint8 usart_num) {
usart_port *port = usart_dev_table[usart_num].base;
/* TC bit must be high before disabling the usart */
while ((port->SR & USART_TC) == 0)
;
/* Disable UE */
port->CR1 = 0;
/* Clean up buffer */
usart_reset_rx(usart_num);
}
/**
* @brief Print a null terminated string to the specified USART
*
* @param usart_num usart to send on
* @param str string to send
*/
void usart_putstr(uint8 usart_num, const char* str) {
char ch;
while((ch = *(str++)) != '\0') {
usart_putc(usart_num, ch);
}
}
/**
* @brief Print an unsigned integer to the specified usart
*
* @param usart_num usart to send on
* @param val number to print
*/
void usart_putudec(uint8 usart_num, uint32 val) {
char digits[12];
int i;
i = 0;
do {
digits[i++] = val % 10 + '0';
val /= 10;
} while (val > 0);
while (--i >= 0) {
usart_putc(usart_num, digits[i]);
}
}
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