/************************************************************************/
/*									*/
/*		capacitive sensor test program				*/
/*									*/
/*		Peter Dannegger						*/
/*									*/
/************************************************************************/
#pragma pl(30000) cd noco

#include <reg51.h>
#include <stdio.h>

#define XTAL    11.0592e6

#define BAUD    1200L

#define CRLF    "\n"

sfr     CKCON   = 0x8F;

sbit	KEY0	= P0^0;


void wait(void)			// wait 512 cycle
{
  unsigned char i;

  for( i = 0; --i; );
}


void main (void)
{
  CKCON = 0x01;			// XTAL / 6 mode  

  PCON |= 0x80;			// SMOD = 1;
  SCON = 0x52;			// TI = 1, UART mode 1
  TMOD = 0x21;			// T1: mode 2, 8bit, T0: mode 1, 16bit
  TH1 = (unsigned char) -(0.5 + XTAL / 6.0 / 16 / BAUD);
  TR1 = 1;			// start T1 for baud rate

  printf( "Hallo Peter" CRLF );
  for(;;){ 						// main loop
    KEY0 = 0;			// discharge
    wait();     
    TR0 = 0;			// stop T0
    TL0 = 0;			// reset T0
    TH0 = 0;
    TR0 = 1;			// start T0
    KEY0 = 1;			// key = tristate, charge
    while( KEY0 == 0 );		// wait until charged
    TR0 = 0;			// stop T0
    printf("Time: %d" CRLF, ((unsigned short)TH0<<8) | TL0 );

    if( TL0 > 25 )
      P1 = 0x00;
    else
      P1 = 0xFF;
  }
}