Classic Computer Magazine Archive ANTIC VOL. 7, NO. 7 / NOVEMBER 1988

Tech Tips

752 Cursor inhibit: 0=visible, 1= invisible
756 Character base register: In graphics 1 and 2, POKE 756, 226 to get lowercase characters. (Default is 224)
764 Contains value of last key pressed (internal code)
767 Scroll start/stop flag: Toggled by pressing [CONTROL] [1]; 0=Scroll enabled, otherwise disabled
832-847 IOCBO: default device for the screen editor. POKE 838,166 and POKE 839,238 to send all screen outputs to the printer. POKE 838,163 and POKE 839,246 to return to normal
928-943 IOCB6: used for screen display
944-959 IOCB7: used by LPRINT, LOAD, SAVE and LIST
2147,2148 One of two locations used by DOS to store LOMEM
2152,2153 The other DOS pointer to LOMEM
5533 Used by DOS to check for presence of DUP.SYS: Zero means DUPSYS is not there
40960 USR here to cold start the BASIC cartridge
41037 USR here to warm start the BASIC cartridge
53277 POKE a 4 here to put paddle and joystick triggers in latch mode; in latch mode, once a trigger is pressed, it stays "pressed" until this location is POKEd with 0
53760 AUDFI: controls the frequency of audio channel one
53761 AUDC1: controls volume and distortion of audio channel one
53762 AUDF2: channel two frequency control
53763 AUDC2: channel two volume and distortion control
53764 AUDF3: channel three frequency control
53765 AUDC3: channel three volume and distortion control
53766 AUDF4: channel four frequency control
53767 AUDC4: channel four volume and distortion control
53768 AUDCTL: master audio channel control byte
54018 PACTL: POKE 52 here to turn the cassette motor on; POKE 60 here to turn the motor back off
58454 CIOV: (more commonly known as $E456) is the entry vector to the central I/O utility in the OS
58460 SETVBV: vertical blank interrupt setup-vector

(This concludes the two-part Carl Evans series which began last month.)

Install a "pause key" in your BASIC programs, using this short listing by James Hague, author of Uncle Henry's Nuclear Waste Dump (Antic, December 1986). After the routine has been installed, holding down [SELECT] and pressing [BREAK] will pause whatever is currently running, be it a BASIC program or machine language subroutine. Press [START] to continue. Also, the [BREAK] key still functions normally alone.

Pause Key must be re-installed after pressing [RESET]. The only things this program can't pause are vertical blank routines and disk I/O.

20 IF PEEK(566)<>0 OR PEEK(567)<>l THEN POKE 273,PEEK(566):POKE 274,PEEK(567)
30 POKE 566,0:POKE 567,1
40 DATA 173,31,208,201,5,208,9,173,31,208,201,6,208,249,104,64,76
50 ?"ANTIC";:GOTO 50:REM For a quick demo, add this line.

Max Metral, 15, lives in Frederick, Maryland and sends along this routine that draws a rectangle, offsets the next rectangle by a specified increment and repeats the process. What you end up with is a flashy screen display.

20 FOR I=1 TO 300 STEP DL
40 PLOT I,0:DRAWTO 0,150-INT(I/2):DRAWTO 300-I,150:DRAWTO 300,INT(I/2):DRAWTO I,0
55 END

Antic pays $25 for every original and exclusive Tech Tip submission that we publish. Send your 8-bit or ST disk and printout to; Antic Tech Tips, 544 Second Street, San Francisco, CA 94107. Tech Tips welcomes very short programs that demonstrate the Atari's powers, simple hardware modifications, or useful macros for popular software.