S3C6410 bare metal UART driver (redefine printf to serial port)

To ensure that S3C6410 has been initialized, usually use UBOOT initialization

//Serial port register

//UART0

#defineULCON0 *((vu32*)0x7F005000) //UART channel 0 line control register

#defineUCON0 *((vu32*)0x7F005004) //UART channel 0 control register

#defineUFCON0 *((vu32*)0x7F005008) //UART channel 0 FIFO control register

#defineUMCON0 *((vu32*)0x7F00500C) //UART channel 0 modem control register

#defineUTRSTAT0 *((vu32*)0x7F005010) //UART channel 0 send/receive status register

#defineUERSTAT0 *((vu32*)0x7F005014) //UART channel 0 receive error status register

#defineUFSTAT0 *((vu32*)0x7F005018) //UART channel 0 FIFO status register

#defineUMSTAT0 *((vu32*)0x7F00501C) //UART channel 0 modem status register

#defineUTXH0 *((vu32*)0x7F005020) //UART channel 0 send buffer register

#defineURXH0 *((vu32*)0x7F005024) //UART channel 0 receive buffer register

#defineUBRDIV0 *((vu32*)0x7F005028) //Channel 0 baud rate divider register

#defineUDIVSLOT0 *((vu32*)0x7F00502C) //UART channel 0 frequency division slot register

#defineUINTP0 *((vu32*)0x7F005030) //Channel 0 interrupt processing register

#defineUINTSP0 *((vu32*)0x7F005034) //UART channel 0 interrupt source processing register

#defineUINTM0 *((vu32*)0x7F005038) //UART channel 0 interrupt mask register

//Author: Chen

//Creation time: 20120220

//Last modified time: 20120220

//Description: S3C6410 serial port related

#include "system.h"

#include "uart.h"

#include "s3c6410_map.h"

///////////////////////////////////////////////////// /////////////////

//Add the following code to support the printf function,

#if 1

#include "stdio.h"        

//Support functions required by the standard library                

struct __FILE

{

inthandle;

};

/* FILE is typedef'd in stdio.h. */

FILE __stdout;      

// define _sys_exit() to avoid using semihost mode   

_sys_exit(int x)

{

x= x;

}

//Redefine fputc function

int fputc(int ch,FILE *f)

{     

Uart0_SendByte((u8)ch);     

returnch;

}

#endif

static const u16UART_SPEED[13][2] ={{1717,0x4924},{858,0x4924},{428,0x4924},{285,0x4924},{213,0x4924},{142,0x4924},{106, 0x4924},{72,0x4924},{70,0x4924},{34,0x4924},{16,0x4924},{7,0x4924},{3,0x4924}};

/****************************************************** *************************************************** ************************

*Function: voidUart0_Init(void)

*Function: Serial port 0 initialization

*Parameters: None

*Return: None

*Depends on: underlying macro definitions

*Author : Chen

*Time: 20120220

* Last modified: 20120220

*Description: Initialize serial port 0

*************************************************** *************************************************** *********************/

void Uart0_Init(u8UART_Speed)

{

PCLK_GATE|= 1 << 1; //UART0 gates PCLK clock, 66mhz

GPIOA->CON&=~(0xff); //Clear previous settings, GPIOA0, GPIOA1

GPIOA->CON|= (HOST | (HOST <<4)); //Set GPIOA0, GPIOA1 to uart mode

ULCON0=0x3; //8 bits per frame //Clear settings//Normal mode, no parity, 1 stop bit

UCON0= (0x1 << 2) | 0x1 | (2 <<10); // Clear control register // Set (PCLK=66MHz) as baud rate clock

UFCON0=0; //Disable FIFO

UMCON0=0; //Disable AFC, nRTS high level is invalid

UBRDIV0 =UART_SPEED[UART_Speed][0]; //Set the integer part of the baud rate

UDIVSLOT0= UART_SPEED[UART_Speed][1]; //Set the decimal part of the baud rate

UINTP0= 0; //Disable UART0 interrupt

UINTSP0= 0; //Set interrupt source

UINTM0= 0; //Disable interrupt mask\

}

/****************************************************** *************************************************** ************************

*Function: voidUart0_SendByte(u8 data)

*Function: Serial port 0 sends a byte

*Parameter: data to be sent

*Return: None

*Depends on: underlying macro definitions

*Author : Chen

*Time: 20120220

* Last modified: 20120220

*Description: Use serial port 0 to send a byte

*************************************************** *************************************************** *********************/

voidUart0_SendByte(u8 data)

{

while(!(UTRSTAT0& (1 <<2))); //Wait for the send buffer to be empty

UTXH0= data; //Write data into the transmit buffer

Now



you can use printf directly to send data to the serial port.