hallo, die helligkeit des balken wird
durch den widerstand bestimmt der vor dem antenneneingang liegt.
die graustufen/schwarz/weiss werden von 0,3v bis 1v geregelt.
je nachdem über welchen pin die daten geschickt werden kann man verschiedene
grautöne erzeugen, es kommt auch auf die einstellung des fernsehers an.
bei 0v bis 0,2v wird der elektrodenstrahl dunkel, für den rücklauf (sync-pin).
ich habe jetzt mal alle herausgenommen (weiss/schwarz), trotzdem erscheint der balken
unverändert.
mfg pebisoft

Code:
//video gen 
//D.5 is sync:1000 ohm + diode to 75 ohm resistor 
//D.6 is video:330 ohm + diode to 75 ohm resistor 


#include <inttypes.h>
#include <stdio.h>
#include <avr/io.h>
#include <avr/interrupt.h>
#include <avr/signal.h>

// cycles = 63.625 * 8 Note NTSC is 63.55 
// but this line duration makes each frame exactly 1/60 sec 
// which is nice for keeping a realtime clock 

#define lineTime 509	// Timer1 Match Value (8 MHz /1 --> 0.000000125 s/cyc 
						//  * 509 --->   0,000063625 s 

//#define ScreenTop 30	// first visible line
//#define ScreenBot 230	// last visible line

#define ScreenTop 100	// first BAR line
#define ScreenBot 150	// last BAR line

//NOTE that the first line of CHARs must be in registers! 
char			syncON, syncOFF; 
//char			v1, v2, v3, v4, v5, v6, v7, v8; 
register unsigned char	v1 asm ("r3");
register unsigned char	v2 asm ("r4");
register unsigned char	v3 asm ("r5");
register unsigned char	v4 asm ("r6");
register unsigned char	v5 asm ("r7");
register unsigned char	v6 asm ("r8");
register unsigned char	v7 asm ("r9");
register unsigned char	v8 asm ("r10");

unsigned char	bMask; 
int				i,LineCount, time; 
char			screen[800], t, ts[10], temp; 


// ---------------------------------------------------------------------
//This is the sync generator. It MUST be entered from 
//sleep mode to get accurate timing of the sync pulses 
//At 8 MHz, all of the sync logic fits in the 5 uSec sync 
//pulse 
//interrupt [TIM1_COMPA] void t1_cmpA(void) 
// ---------------------------------------------------------------------
//SIGNAL (SIG_OVERFLOW1)
SIGNAL (SIG_OUTPUT_COMPARE1A)
{ 
	PORTD	=	syncON;		//start the Horizontal sync pulse 
	TCNT0	=	0;			//count timer 0 at 1/usec 
	LineCount++ ;			//update the curent scanline number 
	switch (LineCount)
	{
//	case 295:				//inverted (Vertical) synch after line 247 NTSC
	case 160:				//inverted (Vertical) synch after line 295 PAL
		syncON	= 0b00100000; 
		syncOFF = 0; 
		break;
//	case 299:				//back to regular sync after line 250  NTSC
	case 314:				//back to regular sync after line 299  PAL
		syncON	= 0; 
		syncOFF = 0b00100000; 
		break;
//	case 313:				//start new frame after line 262 NTSC
	case 348:				//start new frame after line 313 PAL
		LineCount = 1; 
		break;
	default: break; 
	}
	PORTD = syncOFF;		// sync pulse 
} 

// ---------------------------------------------------------------------
// set up the ports and timers  M A I N 
// ---------------------------------------------------------------------
int main(void) 
{ 
//init timer 1 to generate sync 
	OCR1A		= lineTime;	//One NTSC line (509)
	TCCR1B		= 9;		//full speed; clear-on-match MEGA163
	TCCR1A		= 0x00;		//turn off pwm and oc lines 
	TIMSK		= 0x10;		//enable interrupt T1 cmp 

//init ports 
	DDRD		= 0xf0;		//video out and switches 
							//D.5 is sync:1000 ohm + diode to 75 ohm resistor 
							//D.6 is video:330 ohm + diode to 75 ohm resistor 

//init timer 0 to 1/uSec	1 MHZ
	TCCR0		= 2; 

//initialize synch constants 
	LineCount		= 1; 
	syncON			= 0b00000000; 
	syncOFF			= 0b00100000; 

//init software timer 
	t			= 0; 
	time		= 0; 

//enable sleep mode 
	MCUCR		= 0b10000000; 
//#asm ("sei"); 
	sei(); 

//The following loop executes once/video line during lines 
//1-230, then does all of the frame } processing 
	while(1) 
	{ 

// stall here until next line starts 
// sleep enable; mode=idle 
// use sleep to make entry into sync ISR uniform time 

asm volatile ("sleep"); 

		if ((LineCount < ScreenBot) && (LineCount > ScreenTop)) 
		{ 

//Balken zeichnen 
			
			
		} 
	} //while 
	return(0);
} //main
mfg pebisoft