{{htmlmetatags>metatag-robots=()
metatag-title=(WAIT VBL | ugBASIC User Manual)
metatag-keywords=(ugBASIC,Commodore 64,Commodore PLUS/4,ZX Spectrum)
metatag-description=(Manual page for WAIT VBL)
metatag-media-og:image=(:ugbasic:logo-ugbasic-fb.png)
metatag-og:title=(WAIT VBL | ugBASIC User Manual) 
metatag-og:description=(Manual page for WAIT VBL)
}}

====== ugBASIC User Manual ======

===== WAIT VBL  =====

===== SYNTAX =====
     WAIT VBL [raster line]

==== PURPOSE ====



The ''WAIT VBL'' command pauses program execution until a "vertical blank" is encountered. 
This is a signal that is triggered at each screen refresh, which usually occurs at 50 Hz 
in PAL standard and 60 Hz in NTSC standard.

Some video chipsets also allow you to specify a specific raster line, so execution will 
continue when that specific line is reached. If the chipset does not allow this, this 
constraint will be ignored, while still respecting the arrival of a vertical blank.



==== EXAMPLE ====
    WAIT VBL 100


==== ABBREVIATION ====
   WtVb


==== AVAILABLE ON ====
  * Commodore 128 (Zilog Z80)
  * Commodore 128 (MOS 8502)
  * Commodore 64
  * Commodore VIC-20
  * Atari (400/800)
  * Atari XL/XE
  * 
  * Commodore 64+REU
  * Commodore PLUS/4
  * Olivetti Prodest PC128
  * Amstrad CPC 664
  * TRS-80 Color Computer 3
  * TRS-80 Color Computer


==== ANY PROBLEM? ====
If you have encountered a problem using this command, if you think there is a bug or the explanation is unclear, please [[https://github.com/spotlessmind1975/ugbasic/issues/new?title=ISSUE ON WAIT VBL|open an issue]] for this keyword on GitHub. Thank you!===== POWERED BY =====

[[:ugbasic:user:index|{{ :ugbasic:user:logo-ugbasic.png?nolink&600 |}}]]