uart echo back.c

对ADSP21369的原理图和测试程序进行搜集

///////////////////////////////////////////////////////////////////////////////////////
//NAME:     UART Echo Back
//DATE:     7/29/05
//PURPOSE:  UART Example for the ADSP-21369 Ez-kit
//
//USAGE:    Connect the UART connector (P1) to your PC and interact with the EZKit
//          when using the following settings.
//          Bits per Second  -> 19200
//          Data Bits        -> 8
//          Parity           -> odd
//          Stop Bits        -> 2
//          Flow Control     -> None
////////////////////////////////////////////////////////////////////////////////////////
#include <Cdef21369.h>
#include <signal.h>

// The following definition allows the SRU macro to check for errors. Once the routings have
// been verified, this definition can be removed to save some program memory space.
// The preprocessor will issue a warning stating this when using the SRU macro without this
// definition
#define SRUDEBUG  // Check SRU Routings for errors.
#include <SRU.h>

void initDPI(void);		//makes UART0 signal connections to DPI pins
void initUART(void);	//function for initializing the UART
void UARTisr();			//function for receive interrupt
void xmitUARTmessage(char*, int); // function to transmit the welcome message

extern void initPLL_SDRAM(void);    //Initialize PLL to 393 MHz and set up AMI and SDRAM controller


char welcomemessage[] = {"\fHello! \n\r"
                  "This program echoes back whatever you type in...\n\r"}; 
                  
int count,test;                             
                  
                     
main()
{

	*pPICR2 &= ~(0x3E0); //Sets the UART0 receive interrupt to P13

	*pPICR2 |= (0x13<<5); 
	
	initPLL_SDRAM();

	*pUART0LCR=0;
	
    *pUART0IER   = UARTRBFIE;    // enables UART0 receive interrupt
	interrupt(SIG_P13,UARTisr); 
	initDPI();
	initUART();
	
   while(1)
   {
   };
    
}

void initDPI()
{
	
  SRU2(UART0_TX_O,DPI_PB09_I); // UART transmit signal is connected to DPI pin 9
  SRU2(HIGH,DPI_PBEN09_I);
  SRU2(DPI_PB10_O,UART0_RX_I); // connect the pin buffer output signal to the UART0 receive
  SRU2(LOW,DPI_PB10_I);
  SRU2(LOW,DPI_PBEN10_I);      // disables DPI pin10 as input
}

void initUART()
{
	/* Sets the Baud rate for UART0 */	
	*pUART0LCR = UARTDLAB;  //enables access to Divisor register to set baud rate
	*pUART0DLL = 0x1c;      //0x21c = 540 for divisor value and gives a baud rate of19200 for core clock 331.776MHz
    *pUART0DLH = 0x02; 
  
    /* Configures UART0 LCR */ 
    *pUART0LCR = UARTWLS8| 				// word length 8
                 UARTPEN| 				// parity enable ODD parity
                 UARTSTB ; 				// Two stop bits
               
               
    *pUART0RXCTL = UARTEN;       //enables UART0 in receive mode

    *pUART0TXCTL = UARTEN;       //enables UART0 in core driven mode
  
    xmitUARTmessage(welcomemessage,sizeof(welcomemessage));   
}


void UARTisr()
{
 int value;
 
 value = *pUART0RBR;
 
 /* echoes back the value on to the hyperterminal screen*/
 
  
  while ((*pUART0LSR & UARTTHRE) == 0)
  {;
  }
 
  *pUART0THR = value;
  
  /* poll to ensure UART has completed the transfer */
  while ((*pUART0LSR & UARTTEMT) == 0)
   {;
   } 
   
}

void xmitUARTmessage(char*xmit, int SIZE)
{
	int i;
	
	/* loop to transmit source array in core driven mode */   
  for (i=0; i<SIZE; i++)
  {
    // Wait for the UART transmitter to be ready
    do { 
    	;}
    while ((*pUART0LSR & UARTTHRE) == 0);
    
    //Transmit a byte
    *pUART0THR = xmit[i]; 
   }
  
/* poll to ensure UART has completed the transfer */
  while ((*pUART0LSR & UARTTEMT) == 0)
   {;
   } 

}