=========================================
// PIC pin assignment
//
//   PORTA.0 -> AN0 (battery voltage multiplied by R6/(R5+R6)) (analog IN)
//   PORTA.1 -> AN1 (current pickup) (analog IN)
//   PORTA.2 -> spare (OUT)
//   PORTA.3 -> spare  (Analog IN may be temperature reading)
//   PORTA.4 -> BUZZER (OUT)
//   PORTA.5 -> spare (OUT)
//
//   PORTB.0 -> FAN cooler (OUT)
//   PORTB.1 -> D4 data bus for display (OUT)
//   PORTB.2 -> D5 data bus for display (OUT)
//   PORTB.3 -> D6 data bus for display (OUT)
//   PORTB.4 -> D7 data bus for display (OUT)
//   PORTB.5 -> UP key (IN)
//   PORTB.6 -> DOWN key (IN)
//   PORTB.7 -> OK/ENTER key (IN)
//
//   PORTC.0 -> spare (OUT)
//   PORTC.1 -> PWM2 DISCHARGE (OUT)
//   PORTC.2 -> PWM1 CHARGE (OUT)
//   PORTC.3 -> RS register/data for display (OUT)
//   PORTC.4 -> RW read/write for display (OUT)
//   PORTC.5 -> E  enable for display  (OUT)
//   PORTC.6 -> TX  RS232 trasmit  (OUT)
//   PORTC.7 -> RX  RS232 receive (IN)
//=========================================

//=========================================
// Display management routines
//===============================================================================================================================================

procedure lcd4(a,b:byte);                                                       //a command code, b=0 command, b=1 data;
begin
  PORTC.3:=b.0;
  PORTC.4:=0;
  PORTB.1:=a.4;
  PORTB.2:=a.5;
  PORTB.3:=a.6;
  PORTB.4:=a.7;
  PORTC.5:=1;                                                                   //generic 4 bit command or data write
  PORTC.5:=0;
  PORTB.1:=a.0;
  PORTB.2:=a.1;
  PORTB.3:=a.2;
  PORTB.4:=a.3;
  PORTC.5:=1;
  PORTC.5:=0;
  delay_us(1000);
end;


procedure lcd8(a:byte);
begin
  PORTC.3:=0;
  PORTC.4:=0;
  PORTB.1:=a.4;
  PORTB.2:=a.5;                                                                 //generic 8 bit command write
  PORTB.3:=a.6;
  PORTB.4:=a.7;
  PORTC.5:=1;
  PORTC.5:=0;
end;

procedure cls;
begin
  lcd4(1,0);
  delayms(5);
end;

procedure lcd_df_config;
begin
  INTCON.GIE:=0;
  delayms(100);                                                                   //start with 8 bit interface
  lcd8(0x30);
  delayms(10);
  lcd8(0x30);
  delayms(10);
  lcd8(0x30);
  delayms(10);
  lcd8(0x20);
  delayms(10);
  lcd4(0x28,0);                                                                 //now we are on 4 bit interface
  lcd4(0x0C,0);
  lcd4(6,0);
  cls;
  delayms(250);
  lcd4(0x80,0);
  lcd4(32,1);                                                                   //write a space to test
  cls;                                                                          //clear all
  INTCON.GIE:=1;
end;