#define ECLOCK 24000000L
#define BAUD9600 (ECLOCK/(16*9600L))
#define TE 0x08
#define RE 0x04
#define TDRE 0x80
#define RDRF 0x20
#define SCI_BASE_ADDR 0xC8

struct sSCI {
	unsigned short bdr;	// 0x0
	unsigned char cr1;	// 0x2
	unsigned char cr2;	// 0x3
	unsigned char sr1;	// 0x4
	unsigned char sr2;	// 0x5
	unsigned char drh;	// 0x6
	unsigned char drl;	// 0x7
};

#define SCI ((struct sSCI *)SCI_BASE_ADDR)

void sci_init(void)
{
	// init baud rate
	SCI->bdr = BAUD9600;
	
	// enable transmission + recieving
	SCI->cr2 |= TE | RE ;
}

char serial_in(void)
{
	// check that data have been recieved
	while((SCI->sr1 & RDRF) == 0);
	
	// return data
	return SCI->drl;
}

void serial_out(char a)
{
	// check that data register is available (empty)
	while((SCI->sr1 & TDRE) == 0);
	
	// write data
	SCI->drl = a;
}