This function has no arguments. The USED function returns the number of PCG characters used when in the HIRES or PCG modes.
Program Example.
00100 CLS : HIRES : REM Initialise HIRES graphics.
00110 PLOT 255,127 TO INT(RND*512),INT(RND*256)
00120 IF USED < 100 THEN 110 ELSE 100
00130 END