main.h

Bootloader for PIC16F87X (by Niklas Langmaack).

/*
This file contains some routines for the hardware rs232 interface and other small routines.
Here's a lot of assembler-code, although you could do it all in C.
Using C, it's difficult to reach small code sizes...
*/


//==========================================================================================
/*
function to convert two ascii-codes to one real byte
e.g.: 'A' '5' => 165

this is one of the more difficult conversion functions for the compiler,
maybe i'll write this one in assembler soon...
*/
char hex2char(char ander, char einer)
{
   if (einer < 60)
      einer = einer - 48;
   else
      einer = einer - 55;
   if (ander < 60)
      ander = ander - 48;
   else
      ander = ander - 55;
   return ((ander * 16) + einer);
}



//===========================================================================================
//assembler macro for putchr()
asm
{
putchr macro data
   movlw data
   call  _putchr
   endm
}


//===========================================================================================
/*
this function is the equivalent to the original putchar(), just for the
hardware rs232 implementation
*/
void putchr(char chr)
{
   asm bank _txreg
putchr_loop:
   asm
   {
   btfss PIR1, TXIF
   goto  _putchr_loop
   movwf _txreg
   return
   }
}

char getchr()                       //same as above: getchar()
{
   asm   bank _pir1

getchr_loop:
   asm
   {
   btfss _pir1, RCIF
   goto  _getchr_loop
   bcf      _pir1, RCIF
   }
   return rcreg;
}

void put_CR_LF()                    //sends a LineFeed and
{                                // CarriageReturn
   asm putchr 0x0A
   asm putchr 0x0D
}


//============================================================================================
//function to show the menu text
void put_menu_txt()
{
   asm
   {
   putchr 'B'
   putchr 'o'
   putchr 'o'
   putchr 't'
   putchr 'l'
   putchr 'o'
   putchr 'a'
   putchr 'd'
   putchr 'e'
   putchr 'r'
   }
   put_CR_LF();
   asm
   {
   putchr '1'
   putchr ' '
   putchr 'l'
   putchr 'o'
   putchr 'a'
   putchr 'd'
   }
   put_CR_LF();
   asm
   {
   putchr '2'
   putchr ' '
   putchr 's'
   putchr 't'
   putchr 'a'
   putchr 'r'
   putchr 't'
   }
   put_CR_LF();
   asm   putchr '>'
}
//=======================================================================================
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