S3C2440 UART使用笔记

Uart_Init(0,115200);
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void Uart_Init(int pclk,int baud)

{

int i;

if(pclk == 0)

pclk = PCLK;

rUFCON0 = 0x0; //UART channel 0 FIFO control register, FIFO disable

rUFCON1 = 0x0; //UART channel 1 FIFO control register, FIFO disable

rUFCON2 = 0x0; //UART channel 2 FIFO control register, FIFO disable

rUMCON0 = 0x0; //UART chaneel 0 MODEM control register, AFC disable

rUMCON1 = 0x0; //UART chaneel 1 MODEM control register, AFC disable

//UART0

rULCON0 = 0x3; //Line control register : Normal,No parity,1 stop,8 bits
注： bit7:保留位
bit6: 通讯模式0--Normal mode 1--Infrared Tx/Rx Mode
bit[5:3]:校验模式000--Noparity
bit[2]:停止位 0--one stop bit 1--two stop bit
bit[1:0]:没帧数据位 00-5 bits 01--6 bits 10--7bits 11--8bits

// [10] [9] [8] [7] [6] [5] [4] [3:2] [1:0]

// Clock Sel, Tx Int, Rx Int, Rx Time Out, Rx err, Loop-back, Send break, Transmit Mode, Receive Mode

// 0 1 0 , 0 1 0 0 , 01 01

// PCLK Level Pulse Disable Generate Normal Normal Interrupt or Polling

rUCON0 = 0x245; // Control register
注： bit[15:12]: all zero
bit[11:10]:00/10--PCLK 01--UEXTCLK 11-FCLK/n
bit[9]:TX中断设置：0--Pulse 1--Level
bit[8]:RX中断设置：0--Pulse1--Level
bit[7]:Rx Time Out:Disable
bit[6]:1--Generate Rx err interrupt 0--不生成中断
bit[5]bit[4]:Normal Mode
bit[3:2]bit[1:0]: 01--Interrupt or Polling Mode

rUBRDIV0=( (int)(pclk/16./baud+0.5) -1 ); //Baud rate divisior register 0
注： UBRDIVn = (int)( UART clock / ( buad rate x 16) ) –1

//UART1

rULCON1 = 0x3;

rUCON1 = 0x245;

rUBRDIV1=( (int)(pclk/16./baud+0.5) -1 );

//UART2

rULCON2 = 0x3;

rUCON2 = 0x245;

rUBRDIV2=( (int)(pclk/16./baud+0.5) -1 );

注：串口1、2与串口0设置一样

for(i=0;i<100;i++);

}
////////////////////////////////********************************************************************////////////////////////////////////////////////
consoleNum = 0；
Uart_Select( consoleNum )；//whichUart =consoleNum;
Uart_SendByte('n');
////////////////////////////////********************************************************************////////////////////////////////////////////////

void Uart_SendByte(int data)

{

if(whichUart==0)

{

if(data=='n')

{

while(!(rUTRSTAT0 & 0x2));
注： UTRSTATn为只读寄存器，只有低3位有效，该处为死等到发射buffer为空
bit[0]: Receive buffer data ready: 0--Empty 1--buffer has a received data
bit[1]:Transmit buffer empty:0--The buffer not empty 1--empty
bit[2]:Transmit empty:0--not empty 1--Transmitter (transmit buffer & shifter register) empty

// Delay(1); //because the slow response of hyper_terminal

WrUTXH0('r');
注： 发送数据'r'回车

}

while(!(rUTRSTAT0 & 0x2)); //Wait until THR is empty.

// Delay(1);

WrUTXH0(data);
注： 发送数据'n' next line

}

else if(whichUart==1)

{

if(data=='n')

{

while(!(rUTRSTAT1 & 0x2));

//Delay(1); //because the slow response of hyper_terminal

rUTXH1 = 'r';

}

while(!(rUTRSTAT1 & 0x2)); //Wait until THR is empty.

//Delay(1);

rUTXH1 = data;

}

else if(whichUart==2)

{

if(data=='n')

{

while(!(rUTRSTAT2 & 0x2));

//Delay(1); //because the slow response of hyper_terminal

rUTXH2 = 'r';

}

while(!(rUTRSTAT2 & 0x2)); //Wait until THR is empty.

//Delay(1);

rUTXH2 = data;

}

}
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