Tech Tips

USEFUL POKE & PEEK LOCATIONS : PART I

18,19,20           Clock; address 20 increments 60 times a second; 19 increments each
                   time location 20 is reset (about once every 4.25 seconds); 18
                   increments each time location 19 is reset (about once every 18
                   minutes)
65                 POKE a zero here to stop normal program loading sounds (Beeping)
77                 POKE a zero here to turn off the attract mode; must repeat every seven to
                   nine minutes.
82                 Screen left margin (default=2)
83                 Screen right margin (default = 38)
84                 Current cursor row (Graphics 0)
85,86              Current cursor column for all modes (ranges from 0 to 319)
88,89              Upper left-hand screen corner address
93                 Code for the character under the cursor
128,129            BASIC's LOMEM pointer                    
130,131            Contains location of the Variable Name Table 
132,133            Points to the end of the Variable Name Table plus one byte 
134,135            Contains location of the Variable Value Table 
136,137            Points to the beginning of a BASIC program
140,141            Contains location of the String and Array Table; also the end of a
                   BASIC program 
144,145            BASIC's top of memory pointer 
186,187            The line number where a BASIC program has stopped due to ERROR,
                   TRAP, STOP or BREAK
195                The OS code for an error during execution is stored here
212,213            Used to return a value from a USR call
560,561            Contains the location of the display list
580                POKE a 1 here to cause a reboot when [RESET] is pressed
624                Contains current value of PADDLE0 (0-228)                    
625                PADDLE1                    
626                PADDLE2                    
627                PADDLE3                    
628                PADDLE4                    
629                PADDLE5                    
630                PADDLE6                    
631                PADDLE7                    
632                Contains current value of STICK0                    
633                STICK1                    
634                STICK2                      
635                STICK3 
636                PTRIG0: contains 0 if PADDLE0 trigger is pressed; otherwise contains 1
637                PTRIG1 
638                PTRIG2 
639                PTRIG3
640                PTRIG4 
641                PTRIG5 
642                PTRIG6
643                PTRIG7
644                STRIG0: contains 0 if STICK0 trigger is pressed; otherwise contains 1
645                STRIG1
646                STRIG2
647                STRIG3 
660,661            Contains address of upper left corner of text window 
694                Inverse video flag: 0=normal, 128 = inverse 
702                Caps-lock flag: 0=lowercase, 64=uppercase, 128=control characters
708                COLOR0: used for the color of upper-case characters in Graphics 1 and 2
                   (default is 40)
709                COLOR1: used for the color of lowercase characters in Graphics 1 and 2
                   (default is 202)
710                COLOR2: used for the color of inverse uppercase in Graphics 1 and 2 used
                   for background in Graphics 0 (default is 148) 
711                COLOR3: used for the color of inverse lowercase in Graphics 1 and 2
                   (default is 70) 
712                COLOR4: used for the color of the background (border) in Graphics 0
                   (default is: 0) 
736,737            Used by DOS to hold the RUN address of a binary load file 
738,739            Immediate execution address used by DOS to hold the INIT address of a
                   binary load file 
741,742            MEMTOP for BASIC: and the OS (minus 1 to get highest free memory) 
743,744            MEMLO points to the bottom of user memory for BASIC programs

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