//------------------------------------------------------------------------------------
// serial.c
//-----------------------------------------------------------------------------------

//------------------------------------------------------------------------------------
// Includes
//------------------------------------------------------------------------------------
#include <c8051f020.h>                    // SFR declarations
#include <stdio.h>			  // for printf and _getkey functions

//------------------------------------------------------------------------------------
// Global CONSTANTS
//------------------------------------------------------------------------------------


#define SYSCLK 22118400
#define BAUDRATE 9600
#define bool bit
#define true 1
#define false 0
#define null 0

//------------------------------------------------------------------------------------
// Function PROTOTYPES
//------------------------------------------------------------------------------------
void SYSCLK_init(void);
void cross_bar_init(void);
void UART0_init(void);

//------------------------------------------------------------------------------------
// MAIN Routine
//------------------------------------------------------------------------------------
void main (void) 
{
	unsigned char ch;

    WDTCN = 0xDE;   // disable watchdog timer
	WDTCN = 0xAD;
    

	// initialize the system clock
   	SYSCLK_init();
	// initialize the 8051 crossbar
   	cross_bar_init();
	// initialize UART 0 for 9600 baud
   	UART0_init();
	// send a message from UART0

	while (1)
	{
		printf("\n Type a key: ");
   		ch = _getkey();
		printf("\n You typed: %c", ch);
     }
	

}


//------------------------------------------------------------------------------------
// SYSCLK_init
// 
//------------------------------------------------------------------------------------
void SYSCLK_init(void)
{
int i;
    OSCXCN = 0x67;      // start external oscillastor with 22.1184 MHz crystal
	 for (i = 0; i < 256; i++) ;  // wait for oscillator to start


	 while (! (OSCXCN & 0x80)) ;    // wait for crystal osc. to settle
	 OSCICN = 0x88; // select external oscillator as SYSCLK source 
	                // and enable missing clock detector
}




//------------------------------------------------------------------------------------
// cross_bar_init
// 
//------------------------------------------------------------------------------------
void cross_bar_init(void)
{
	XBR0 = 0x04;
	XBR2 = 0x40;
    P0MDOUT = 0x01; // output configuration for port P0
}


//------------------------------------------------------------------------------------
// UART0_init
// 
//------------------------------------------------------------------------------------
void UART0_init(void)
{
   SCON0 = 0x50; // SCON0: mode 1 8-bit UART, enable RX
   TMOD = 0x20;  // TMOD: 
   TH1 = -(SYSCLK/BAUDRATE/16); // set Timer 1 reload value for correct baud rate
   TR1 = 1;   // start timer 1
   CKCON |= 0x10;     // timer 1 uses SYSCLK as time base
   PCON |= 0x80;      // SMOD0 = 1 disable baud rate divide by 2
   TI0 = 1;           // set transmit TX0 to ready


}