/*
	NAME: C-code for 121 Prototype Board Testing
	CODE: ANSI-C for 68HC11A0
  TOOLS: Whitesmiths c-compiler ver 3.02
	FILE: test.c
 AUTHOR: S.C. Petersen
	 REV: 1.0 Fall-99/scp
			2.0 Spring-2000/scp

	This is a simple test program to be used as a first checkout of your lab prototype board.
	An infinite loop writes ascii characters from 0h to 255h out the serial
	port and to the embedded HC11 Port-D, which can be used to verify program
	execution independent of the serial port.
 */

#include <stdio.h>
#include <io.h>

#define TDRE    0x80             /* Transmit Ready Bit */
#define RDRF	0x20		 /* Receive Register Full Bit */
#define RDRF_W_ERRS	0x2E		 /* RDRF + OR + NF + FE */
#define MISO	0x04
#define MOSI	0x08

#define FIFO_SZ 0x1000

const unsigned char ready[] = "\r\nI'm completely operational, and all my circuits are functioning perfectly.\r\n";

_PORT	char	px	@0x7000;
_PORT	char	py	@0x7800;

unsigned char x, y;
unsigned char tic, ptic;
unsigned char ticks[ 3 ]; //sec min hr

unsigned int  ihead, itail; //add chars to tail, read from head
				 //head points to valid char, tail points to unused char
				 //if head == tail then no chars!
unsigned char ififo[ FIFO_SZ ];
unsigned int  ohead, otail;
unsigned char ofifo[ FIFO_SZ ];

@interrupt void tick()
{
	TOC2 = TCNT + 0xf415;	/* 0xf424 - 0xe (cycles to service ISR) - 0x1 (average latency) */
	TFLG1 = 0x40;		/* clear OC2F bit */

	++tic;
	if( tic & 0x01 ) ++ticks[ 0 ];  // divide-by-two

	if( ticks[ 0 ] > 59 )
	{
		ticks[ 0 ] = 0;
		++ticks[ 1 ];
		if( ticks[ 1 ] > 59 )
		{
			ticks[ 1 ] = 0;
			++ticks[ 2 ];
			if( ticks[ 2 ] > 23 )
	 		{
		 		ticks[ 2 ] = 0;
			} //t2
		} //t1
	} //t0

	return;
}

@interrupt void scisr()
{
	if( ( SCSR & RDRF_W_ERRS ) == RDRF )
	{
		if( itail != ( ihead - 1 ) )
		{
			ififo[ itail ] = SCDR;
			++itail;
			if( itail >= FIFO_SZ )
				itail = 0;
		}
	}
	else if( SCSR & TDRE )
	{
		if( ohead != otail )
		{
			SCDR = ofifo[ ohead ];
			++ohead;
			if( ohead >= FIFO_SZ )
				ohead = 0;
		}
		if( ohead == otail )		//if FIFO is empty
		{
			ohead = 0;  otail = 0;	//reset pointers
			SCCR2 = SCCR2 & 0x7f;	//clear Transmit Interrupt Enable bit
		}
	}

	return;
}

int putchar( char c )
{
	_asm("sei");		//mask interrupts for this call

	if( ( otail == ohead ) && ( SCSR & TDRE ) )	//if FIFO and SCI Tx buffer are empty
	{
		SCDR = c;					//write to the port
	}
	else if( otail != ( ohead - 1 ) )		//else ensure FIFO isn't full
	{
		ofifo[ otail ] = c;			//and write to the FIFO
		++otail;
		if( otail >= FIFO_SZ )
			otail = 0;
	}

	_asm("cli");

	SCCR2 = SCCR2 | 0x80;		//set Transmit Interrupt Enable bit

	return c;
}

int getchar()
{
	if( ihead != itail )
	{
		_asm("sei");		//mask interrupts for this case

		x = ififo[ ihead ];
		++ihead;
		if( ihead >= FIFO_SZ )
			ihead = 0;

		_asm("cli");
	}
	else
	{
		ihead = 0;  itail = 0;		//reset pointers
		x = 0;				//return NULL
	}

	return( x );
}

void main(void)
{
	/* initialize fifos */
	ihead = 0; itail = 0;
	ohead = 0; otail = 0;
	/* initialize Port D Data Direction Register */
	DDRD = ( DDRD & 0xfb ) | 0x08;
//	PORTD = PORTD & 0xf7; //clear MOSI
	/* enable Receiver Interrupt Enable */
	SCCR2 = SCCR2 | 0x20;

	putchar( 0x1b ); putchar( 0x5b ); putchar( 0x3f ); putchar( 0x37 ); putchar( 0x68 );  //enable auto wrap to new line
	puts( ready );

	/* main event loop */
	while( 1 )
	{
		x = getchar();
		if( x != 0 )
		{
			putchar( x );
			if( x == 'J' )
			{
				putchar( 'A' );
				putchar( 'S' );
				putchar( 'O' );
				putchar( 'N' );
			}
		}
		else if( ticks[ 0 ] != ptic )
		{
			ptic = ticks[ 0 ];

			/* output time *************************************************************/
			putchar( 0x1b ); putchar( 0x37 ); //save cursor position
			//send cursor to 0;70
			putchar( 0x1b ); putchar( 0x5b ); putchar( '0' ); putchar( ';' ); putchar( '7' ); putchar( '0' ); putchar( 0x48 );
	
			printf( "%2d:%02d:%02d", ticks[2], ticks[1], ticks[0] );
	
			putchar( 0x1b ); putchar( 0x38 ); //restore cursor position
			/***************************************************************************/
		}
	} // end while( 1 )
}