rt-thread-official/libcpu/arm/lpc24xx/serial.c

150 lines
3.0 KiB
C

/*
* File : serial.c
* This file is part of RT-Thread RTOS
* COPYRIGHT (C) 2006, RT-Thread Development Team
*
* The license and distribution terms for this file may be
* found in the file LICENSE in this distribution or at
* http://openlab.rt-thread.com/license/LICENSE
*
* Change Logs:
* Date Author Notes
* 2006-08-23 Bernard first version
*/
#include <rthw.h>
#include <rtthread.h>
#include "lpc214x.h"
#include "board.h"
void rt_serial_init(void);
#define PCLK 18000000
#define BAUD_RATE 115200
#define U0PINS 0x00000005
/**
* @addtogroup LPC2100
*/
/*@{*/
/**
* This function is used to display a string on console, normally, it's
* invoked by rt_kprintf
*
* @param str the displayed string
*/
void rt_console_puts(const char* str)
{
while (*str)
{
rt_serial_putc (*str++);
}
}
#define UART_RX_BUFFER_SIZE 64
static rt_uint8_t uart_rx_buffer[UART_RX_BUFFER_SIZE];
static rt_uint32_t uart_read_index, uart_save_index;
/**
* This function initializes serial
*/
void rt_serial_init()
{
unsigned long Fdiv;
PINSEL0 = 0x00000050; /* RxD0 and TxD0 */
rt_memset(uart_rx_buffer, 0, sizeof(uart_rx_buffer));
uart_read_index = uart_save_index = 0;
U0LCR = 0x83; /* 8 bits, no Parity, 1 Stop bit */
/*PCLK select is 00,so /4*/
Fdiv = ( PCLK / 16 ) / BAUD_RATE ; /*baud rate */
U0DLM = Fdiv / 256;
U0DLL = Fdiv % 256;
U0FCR = 0x00; /* Enable and reset TX and RX FIFO. */
U0LCR = 0x03; /* DLAB = 0 */
}
/* save a char to serial buffer */
void rt_serial_savechar(char ch)
{
rt_base_t level;
/* disable interrupt */
level = rt_hw_interrupt_disable();
uart_rx_buffer[uart_save_index] = ch;
uart_save_index ++;
if (uart_save_index >= UART_RX_BUFFER_SIZE)
uart_save_index = 0;
/* if the next position is read index, discard this 'read char' */
if (uart_save_index == uart_read_index)
{
uart_read_index ++;
if (uart_read_index >= UART_RX_BUFFER_SIZE)
uart_read_index = 0;
}
/* enable interrupt */
rt_hw_interrupt_enable(level);
}
/**
* This function read a character from serial without interrupt enable mode
*
* @return the read char
*/
char rt_serial_getc()
{
char ch;
rt_base_t level;
/* disable interrupt */
level = rt_hw_interrupt_disable();
if (uart_read_index != uart_save_index)
{
ch = uart_rx_buffer[uart_read_index];
uart_read_index ++;
if (uart_read_index >= UART_RX_BUFFER_SIZE)
uart_read_index = 0;
/* enable interrupt */
rt_hw_interrupt_enable(level);
return ch;
}
/* enable interrupt */
rt_hw_interrupt_enable(level);
return 0;
}
/**
* This function will write a character to serial without interrupt enable mode
*
* @param c the char to write
*/
void rt_serial_putc(const char c)
{
/*
to be polite with serial console add a line feed
to the carriage return character
*/
if (c=='\n')
{
while (!(U0LSR & 0x20));
U0THR = '\r';
}
while (!(U0LSR & 0x20));
U0THR = c;
}
/*@}*/