// --------------------------------------
// DIY-A1 Frequency Display Module 
// MCU Code Version 1.00
// 2002.07.08
// Designed by Rong Xinhua, BD6CR
// E-mail: bd6cr@qsl.net
// --------------------------------------
// Hardware: DIY-A1 REV A
// http://www.qsl.net/bd6cr/fc
// Order: http://www.qsl.net/bd6cr/store
// AT89C2051 + 74HC390 + C-284CI
// Clock: 12MHz
// --------------------------------------
// Compiler:
// KEIL 8051 C Compiler V5.20 (DLL: 1.24)
// (uVision/51 for Windows Version 1.24)
// Download: http://www.mcu51.com
// --------------------------------------

#include <at892051.h>

//pin definition
#define MHZ_BUTT P3_3
#define OFFSET P3_2
#define SEG1 P3_7
#define SEG2 P3_4
#define SEG3 P3_1
#define SEG4 P3_0
#define FINPUT P3_5
#define LEDDATA P1

//constant definition
//frequency offset for 139A receiver
#define offset1 -4650	//default, usually set to 0. -4650 means f(rx) = f(vfo)-465.0kHz
#define offset2 4650

//variable definition
unsigned char convert[10] = {0x3F,0x21,0x5B,0x73,0x65,0x76,0x7E,0x23,0x7F,0x77};
unsigned char digits[4] = {0xFF,0xFF,0xFF,0xFF};
unsigned char timer0_count = 0, timer1_count = 0;
unsigned char temp1, temp2, temp3;
unsigned char tag = 0, mhz = 0;

//subroutines
void timer0() interrupt 1 using 1 {
  timer0_count ++;
  if (timer0_count == 16) {
	EA = 0;
	tag = 1;
	TR1 = 0;
	TR0 = 0;
	temp1 = timer1_count;
	temp2 = TH1;
	temp3 = TL1;
	timer0_count = 0;
	TH0 = 189;
        TL0 = 208;
	timer1_count = 0;
	TH1 = 0;
	TL1 = 0;
	TR0 = 1;
	TR1 = 1;
	EA = 1;
  }
}

void timer1() interrupt 3 using 2 {
  timer1_count ++;
}

unsigned char bcd_seg(unsigned char n) {
  if (n < 10) return(convert[n]);
  return(0);
}

void delay() {
        int j;
          for (j=0; j< 120; j++) {
		if (MHZ_BUTT == 0) mhz = 1;	//MHZ_BUTT pressed?
	  }     //delay some time

}

void display() {
          LEDDATA = digits[3];
	  SEG4 = 0;
          delay();
	  SEG4 = 1;
          LEDDATA = digits[2];
	  SEG3 = 0;
          delay();
          SEG3 = 1;
          LEDDATA = digits[1];
	  SEG2 = 0;
          delay();
	  SEG2 = 1;	  
          LEDDATA = digits[0];
	  SEG1 = 0;
          delay();
	  SEG1 = 1;	  
}

//main goes here
main()
{
        unsigned long count;

        TMOD = 0X51;    //TMR1 external input: 0x51
	IE = 0X8A;
        IP = 0X08;      //Timer1 piority higher than timer0
        TH0 = 189;
        TL0 = 208;
	TH1 = 0;
	TL1 = 0;
    	TR0 = 1;    	//start TMR0 here
	TR1 = 1;


        while (1) {

        if (tag) {
          display();
          display();
          count = temp1 * 65536;
          display();
          display();
          count = count + temp2 * 256;
          display();
          display();
          count = count + temp3;
          display();
          display();

	  if (OFFSET) count = count + (offset1);
	  else count = count + (offset2);
	  display();
	  display();

	  if (mhz) count = count / 100;
	  else 	  count = count % 10000;
          display();
          display();

          digits[3] = bcd_seg(count / 1000);
	  if (mhz) digits[3] = digits[3] + 128;
          display();
          display();

	  count = count % 1000;
          display();
          display();

          digits[2] = bcd_seg(count / 100);
          display();
          display();

          count = count % 100;
          display();
          display();

          digits[1] = bcd_seg(count / 10);
	  if (mhz == 0) digits[1] = digits[1] + 128;
          display();
          display();

	  count = count % 10;
          digits[0] = bcd_seg(count);
	  tag = 0;
	  mhz = 0;
	}
        display();
        display();

	}
}