APPENDIX TWELVE



735            2DF            PBUFSZ
     Print buffer size; moved from 30 ($1E) on the 400/800.

745            2E9            HNDLOD
     Relocatable loader routine handler flag.

746-749        2EA-2ED        DVSTAT
     Additional device status registers to contain information re-
     turned to the computer by the peripheral after the new type 3
     and 4 polls. The bytes contain:

     746/747   LSB/MSB of the handler size (must be an even
               number)
     748       Device SIO address to be used for loading
     749       Peripheral revision number

     The new poll types are fully explained in the 1200XL operating
     system manual; earlier poll types are described in the 400/800
     hardware manual. Basically, type 3 is an "are you there?" poll
     (device address $4F, command byte $40, AUX1 $4F, AUX2 $4F,
     checksum normal), and poll 4 is a null poll (values $4F, $40, $4E
     and $4E, respectively; checksum normal).

756            2F4            CHBAS
     Character set select; default of 224. The international set can be
     selected by POKE 756,204 ($CC). On the 1200XL, the value in
     CHBAS is switched with that in CHSALT (619; $26B) whenever
     CTRL-F4 is used to toggle the alternate character set. The val-
     ues in the two registers are swapped and LED 2 is lit.

757            2F5            NEWROW
     Moved from 96 ($60) in the 400/800.

758,759        2F6,2F7        NEWCOL
     Moved from 97,98 ($61,$62) in the 400/800.

760            2F8            ROWINC
     Moved from 121 ($79) in the 400/800.

761            2F9            COLINC
     Moved from 122 ($7A) in the 400/800.

782            30E            JMPERS
     Storage for hardware option jumpers on the 1200XL, intended to
     tell the OS how the system is configured; if bit 0 (POT 4) is not set
     (0), then the self-test will run. Bits 1-7 are unused. Used only in
     the 1200XL.