XCore Exchange

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chan <: ((unsigned)data);

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#include <xs1.h>

#define BIT_RATE 115200
#define BIT_TIME XS1_TIMER_HZ / BIT_RATE

out port TXD = XS1_PORT_1J;

void txByte (out port TXD, char byte);

int main()
{
    char msg[]="Hello World!\n";
    int bytes=sizeof(msg);
    // send the message continuously, so you don't miss it
    while(1){
        for (int i=0;i<bytes;i++) {
            txByte(TXD,msg[i]);
        }
    }
    return 0;
}

void txByte(out port TXD, char byte) {
	unsigned time;
	timer t;
	/* get initial time */
	t :> time;
	/* send start bit */
	TXD <: 0;
	time += BIT_TIME;
	t when timerafter(time) :> void;
	/* send data bits */
	for (int i=0; i<8; i++) {
		TXD <: >> byte;
		time += BIT_TIME;
		t when timerafter(time) :> void;
	}
	/* send stop bit */
	TXD <: 1;
	time += BIT_TIME;
	t when timerafter(time) :> void;
}

Code: Select all

// Simple UART demo for XC-1 board

#include <xs1.h>
#include <platform.h>

#define BIT_RATE 57600
#define BIT_TIME XS1_TIMER_HZ / BIT_RATE

void txByte(char);
unsigned char rxByte(void);

out port TXD = PORT_UART_TX;
in port  RXD = PORT_UART_RX;

int main(void)
{	
	int c;

	while (1)
	{
		c = rxByte();
		txByte(c);
	}
	return 0;
}

unsigned char rxByte(void)
{
   unsigned data = 0, time;
   int i;
   unsigned char c;

   // Wait for stop bit
   RXD when pinseq (1) :> int _;

   // wait for start bit
   RXD when pinseq (0) :> int _ @ time;
   time += BIT_TIME + (BIT_TIME >> 1);

   // sample each bit in the middle.
   for (i = 0; i < 8; i += 1)
   {
      RXD @ time :> >> data;
      time += BIT_TIME;
   }

   // reshuffle the data.
   c = (unsigned char) (data >> 24);

   return (c);
}

void txByte(char c)
{
	unsigned time ;
	timer t;

	/* input initial time */
	t :> time ;

	/* output start bit */
	TXD <: 0;
	time += BIT_TIME ;
	t when timerafter ( time ) :> void ;

	/* output data bits */
	for ( int i=0; i <8; i ++)
	{
		TXD <: >> c ;
		time += BIT_TIME ;
		t when timerafter ( time ) :> void ;
	}

	/* output stop bit */
	TXD <: 1;
	time += BIT_TIME ;
	t when timerafter ( time ) :> void ;
}