Undercolor/850106/Hints and Tips

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UnderColor, Volume 1, Number 6, March 8, 1985

• Title: Hints and Tips
• Author: Terry Kepner
• Synopsis: Good stuff.
• Page Scans: Link

Article

Programming — Rather than using INKEY$ and a loop when you want the computer to wait before continuing, use Exec 44539 in your program. It’s shorter and faster. The computer will pause until any key is pressed, then continue.

Printer — Here’s a two line program to screen dump graphics modes 0, 2, and 4 to a DMP-100:

10 SCREEN1,0:FOR X=1 TO 4:PPINT#-2,CHR$(18):NEXT X:FOR X=0 TO 191 STEP7: PRINT#-2,CHR$(27);CHR$(16;CHR$(0);CHR$(112);:FOR Y=0 TO 255:G=128:FOR Z=0 TO 6:IF X+Z<192 AND POINT (Y,X+Z) THEN G = G + 2 C

20 NEXT Z;PRINT#-2,CHR$(G);:NEXT Y;PRINT#-2, CHR$(13);:NEXT X::PRINT#-2,CHR$(30)

Programming — To locate the IRQ vector, type PRINT HEX$(PEEK(&H010D)); HEX$(PEEK(&H010E)).

Disk Basic — To detect the presence of disk drives on a Color Computer from within a program, PEEK(&HCO00) should return decimal (&H44) if the disk ROMpak is in place.

Programming—Edit has three additional commands not mentioned in the manual: A, cancel all changes, list line, and stay in edit mode; Q, cancel all changes, leave edit mode (leaves variables’ values unchanged); and E, keep changes and leave edit mode (same as pressing Enter).

Programming—Want to know what all those hexadecimal numbers mean in decimal? Type PRINT &Hxxxx, where xxxx is the hex number. Going the other way is just as simple: PRINT HEX$(decimal).

Hardware—Need to drive a separate audio amplifier? Pin 3 on the RF modulator, teamed with a ground line from the main circuit board, will provide the necessary connections. Pin 3 is the third pin from the rear of the computer on the RF modulator.

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