/* 
 * Title       : temp.c
 * Description : Temperature
 * Author      : KAWAMOTO Yasuhisa
 * URL         : http://www.devdrv.co.jp
 * Date        : 09/24/2003
 */
 
#include <c8051f330.h>

typedef unsigned int   uint;
typedef unsigned char  uchar;
typedef unsigned short ushort;
typedef unsigned long  ulong;

/****************************************************************************/
/* System Dependent Values                                                  */
/****************************************************************************/
#define SYSCLK   24500000/8
#define BAUDRATE       9600
#define SAMPLE_RATE       1
#define INT_DEC         256

#define CTS P0_2
#define RTS P0_7
#define LED P2_0

/****************************************************************************/
/* Global variables                                                         */
/****************************************************************************/
long result = -1;

/****************************************************************************/
/* Function prototypes                                                      */
/****************************************************************************/
void sysclk_init(void);
void port_init(void);
void uart0_init(void);
void uart0_put(uchar);
void timer2_init(int);
void adc0_init(void);

/****************************************************************************/
/****************************************************************************/
/* Main program loop                                                        */
/****************************************************************************/
/****************************************************************************/
void main(void)
{
	long temp;
	
	PCA0MD &= ~0x40;
	sysclk_init();
	port_init();
	uart0_init();
	adc0_init();
	timer2_init(SYSCLK/INT_DEC/SAMPLE_RATE);
	
	EA = 1;
	
	RTS = 0;
	
	while(1)
	{
		if(0 < result)
		{
			EA = 0;
			temp = result;
			result = -1;
			EA = 1;
			
			temp = temp / INT_DEC;
			temp = temp * 1154 / 1024;
			temp = temp - 271;
			temp = temp - 15;
			
			while((TI0 == 0) || (CTS == 1));
			TI0 = 0;
			SBUF0 = temp;
			LED = ~LED;
		}
		PCON |= 0x01;
	}
}

/****************************************************************************/
/* sysclk_init                                                              */
/****************************************************************************/
void sysclk_init(void)
{
	OSCICN = 0x80;
	RSTSRC = 0x04;
}

/****************************************************************************/
/* port_init                                                                */
/****************************************************************************/
// P0.0
// P0.1
// P0.2 CTS   (<-- XPort)
// P0.3
// P0.4 TX    (--> XPort)
// P0.5 RX    (<-- XPort)
// P0.6
// P0.7 RTS   (--> XPort)
// P2.0 LED   (--> LED)
void port_init(void)
{
	XBR0    = 0x01;
	XBR1    = 0x40;
	P0SKIP  = 0x00;
	P1SKIP  = 0x00;
	P0      = 0x24;
	P1      = 0x00;
	P2      = 0x01;
	P0MDOUT = 0x90;
	P1MDOUT = 0x00;
	P2MDOUT = 0x00;
}

/****************************************************************************/
/* uart0_init                                                               */
/****************************************************************************/
void uart0_init(void)
{
	SCON0 = 0x10;
	if(SYSCLK/BAUDRATE/2/256 < 1)
	{
		TH1 = -(SYSCLK/BAUDRATE/2);
		CKCON |= 0x08;
	}
	else if(SYSCLK/BAUDRATE/2/256 < 4)
	{
		TH1 = -(SYSCLK/BAUDRATE/2/4);
		CKCON |=  0x01;
		CKCON &= ~0x0A;
	}
	else if(SYSCLK/BAUDRATE/2/256 < 12)
	{
		TH1 = -(SYSCLK/BAUDRATE/2/12);
		CKCON &= ~0x0B;
	}
	else
	{
		TH1 = -(SYSCLK/BAUDRATE/2/48);
		CKCON |=  0x02;
		CKCON &= ~0x09;
	}
	
	TL1 = 0xFF;
	TMOD |= 0x20;
	TMOD &= ~0xD0;
	TR1 = 1;
	TI0 = 1;
}

/****************************************************************************/
/* timer2_init                                                              */
/****************************************************************************/
void timer2_init(int counts)
{
	TMR2CN  = 0x00;
	CKCON  |= 0x30;
	
	counts = -counts;
	TMR2RLL = counts;
	TMR2RLH = counts >> 8;
	TMR2L   = 0xFF;
	TMR2H   = 0xFF;
	ET2     = 0;
	TR2     = 1;
}

/****************************************************************************/
/* adc0_init                                                                */
/****************************************************************************/
void adc0_init(void)
{
	AMX0P = 0x10;
	AMX0N = 0x11;
	ADC0CF = (SYSCLK/7500000) << 3;
	REF0CN = 0x0F;
	EIE1 |= 0x08;
	ADC0CN = 0x82;
}

/****************************************************************************/
/* adc0_isr                                                                 */
/****************************************************************************/
void adc0_isr(void) interrupt 10
{
	static unsigned intdec = INT_DEC;
	static long accumulator = 0L;
	ushort adc0;
	
	AD0INT = 0;
	
	adc0 = ADC0H;
	adc0 = (adc0 << 8) | ADC0L;
	
	accumulator += adc0;
	intdec--;
	if(intdec == 0)
	{
		result = accumulator;
		accumulator = 0L;
		intdec = INT_DEC;
	}
}