/*****************************************************************************
 * File:        serial.c
 * Date:        Sat Jun  8 16:51:19 NZST 2002
 * Author:      Clark Mills (clark@kiwi.gen.nz)
 * Description: Play with the serial port on an AT90S8535 MCU
 * License:     GPL
 *****************************************************************************/

#define UBRR	0x09		// UART Baud Rate Register
#define USR	0x0B		// UART Status Register
#define UCR	0x0A		// UART Control Register

/* USR Register Bits */
#define UDRE	5		// set when ok to send a byte
#define RXC	7		// set when byte in receive register

/* UCR Register Bits */
#define RXEN	4		// enable receive on UART
#define TXEN	3		// enable transmit on UART

#include <avr/io.h>

// prototypes
int getc( void );
void putc( int ch );
void stepper_init( void );
void stepper_delay( void );
void led_init( void );
void serial_init( void );
void serial_putc( int ch );
int serial_getc( void );

/*****************************************************************************
 * Test it
 */
void main(void)
{
	char ch;

	stepper_init();
	led_init();
	serial_init();

	while (1)					// Forever...
	{
		ch = serial_getc();
		serial_putc( ch );

		// sbi(PORTB,PB5);	// LED Off
		// cbi(PORTB,PB5);	// LED On

/*
		// Clockwise Port 1
		sbi(PORTD,PD4); stepper_delay(); cbi(PORTD,PD4);
		sbi(PORTD,PD4); sbi(PORTB,PB0); stepper_delay(); cbi(PORTB,PB0); cbi(PORTD,PD4);
		sbi(PORTB,PB0); stepper_delay(); cbi(PORTB,PB0);
		sbi(PORTB,PB0); sbi(PORTD,PD6); stepper_delay(); cbi(PORTD,PD6); cbi(PORTB,PB0);
		sbi(PORTD,PD6); stepper_delay(); cbi(PORTD,PD6);
		sbi(PORTD,PD6); sbi(PORTD,PD5); stepper_delay(); cbi(PORTD,PD5); cbi(PORTD,PD6);
		sbi(PORTD,PD5); stepper_delay(); cbi(PORTD,PD5);
		sbi(PORTD,PD5); sbi(PORTD,PD4); stepper_delay(); cbi(PORTD,PD4); cbi(PORTD,PD5);
*/

		// Clockwise Port 2
		sbi(PORTB,PB4); sbi(PORTB,PB1); stepper_delay(); cbi(PORTB,PB1); cbi(PORTB,PB4);
		sbi(PORTB,PB4); stepper_delay(); cbi(PORTB,PB4);
		sbi(PORTB,PB3); sbi(PORTB,PB4); stepper_delay(); cbi(PORTB,PB4); cbi(PORTB,PB3);
		sbi(PORTB,PB3); stepper_delay(); cbi(PORTB,PB3);
		sbi(PORTB,PB2); sbi(PORTB,PB3); stepper_delay(); cbi(PORTB,PB3); cbi(PORTB,PB2);
		sbi(PORTB,PB2); stepper_delay(); cbi(PORTB,PB2);
		sbi(PORTB,PB1); sbi(PORTB,PB2); stepper_delay(); cbi(PORTB,PB2); cbi(PORTB,PB1);
		sbi(PORTB,PB1); stepper_delay(); cbi(PORTB,PB4);
	}

}

/*****************************************************************************
 * LED serial port
 */
void led_init( void )
{
	sbi(DDRB,PB5);		// enable PB5 as output	LED
	sbi(PORTB,PB5);		// LED Off
}

/*****************************************************************************
 * Init stepper port
 */
void stepper_init( void )
{

	// Enable Port 1
	sbi(DDRD,PD4);		// enable PD4 as output
	sbi(DDRB,PB0);		// enable PB0 as output
	sbi(DDRD,PD6);		// enable PD6 as output
	sbi(DDRD,PD5);		// enable PD5 as output

	// Enable Port 2
	sbi(DDRB,PB1);		// enable PB1 as output
	sbi(DDRB,PB2);		// enable PB2 as output
	sbi(DDRB,PB3);		// enable PB3 as output
	sbi(DDRB,PB4);		// enable PB4 as output
}

/*****************************************************************************
 * Delay
 */
void stepper_delay( void )
{
	int j, k;

	for (j=0; j<40; j++)
	{
		for (k=0; k<100; k++)
			sbi(DDRB,PB5);		// enable PB5 as output	LED
	}
}

/*****************************************************************************
 * Init serial port
 */
void serial_init( void )
{
	// outp( 0x19, UBRR );				// 9600 baud @ 4Mhz
	outp( 0x41, UBRR );				// 9600 baud @ 10Mhz
	outp( 1<<RXEN | 1<<TXEN, UCR );			// RX & TX enable
}

/*****************************************************************************
 * Send char out serial port
 */
void serial_putc( int ch )
{
	while ( (inp(USR) & 1<<UDRE ) == 0 )		// Wait to send...
		;
	outp( ch, UDR );				// send
}

/*****************************************************************************
 * Read char from serial port
 */
int serial_getc( void )
{
	while ( (inp(USR) & 1<<RXC ) == 0 )		// Wait to receive...
		;
	return inp( UDR );				// receive
}

/**********************************  EOF  ************************************/