Overlaying Stationary Text

[menager]

I want to overlay my callsign on the screen. So far, I’ve got it to sweep across and down the screen, but I just want it to remain in the corner. I know it has something to with the frame rate, but I can’t figure out what part of the TVout library is responsible for that.

[Michael]

Can you post your code so I can see if something is missing? You can replace your callsign with XXXXXX if you want.

[menager]

#include "TVout.h"
#include "fontALL.h"
TVout TV;

void setup() 
 {
  TV.begin(NTSC,90,40); 
  
  TV.select_font(font6x8); 
 }
 
void loop()
 {
  TV.set_cursor(0,6);
  TV.print("XXXXX");
  delay(60);
 }

• This reply was modified 7 years, 11 months ago by Michael.

[Michael]

When using the Video Experimenter, you have to enable overlay capability with some special code. This is demonstrated in all the example projects like: the overlay example

Try this code for your sketch. Note the initOverlay() function and the ISR(INT0_vect) function. They are required.

#include "TVout.h"
#include "fontALL.h"
TVout TV;

void setup() 
 {
  TV.begin(NTSC,90,40); 
  initOverlay();
  TV.select_font(font6x8); 
 }
 
// Initialize ATMega registers for video overlay capability.
// Must be called after tv.begin().
void initOverlay() {
  TCCR1A = 0;
  // Enable timer1.  ICES0 is set to 0 for falling edge detection on input capture pin.
  TCCR1B = _BV(CS10);

  // Enable input capture interrupt
  TIMSK1 |= _BV(ICIE1);

  // Enable external interrupt INT0 on pin 2 with falling edge.
  EIMSK = _BV(INT0);
  EICRA = _BV(ISC01);
}

// Required to reset the scan line when the vertical sync occurs
ISR(INT0_vect) {
  display.scanLine = 0;
}

void loop()
 {
  TV.set_cursor(0,6);
  TV.print("XXXXX");
  delay(60);
 }

• This reply was modified 7 years, 11 months ago by Michael.

[menager]

Thanks Michael! It worked.

I did not understand the purpose those two functions. Definitely going to continue reading up on the TVOut documentation.

[Author]

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