750,751



     value of the status register of the drive controller. For the 850
     Interface, it holds the status for DSR,CTS,CRX and RCV when
     concurrent I/O is not active (see the 850 Interface Manual). It also
     contains the AUX2 byte value from the previous operation (see
     the IOCB description at 832 to 959; $340 to $3AF).
     748 ($2EC) is the maximum device time-out value in seconds. A
     value of 60 here represents 64 seconds. This value is passed back
     to location 582 ($246) after every disk status request. Initialized to
     31.
     749 ($2ED) is used for number of bytes in output buffer. See 850
     Manual, p. 43.
     When concurrent I/O is active, the STATUS command returns
     the number of characters in the input buffer to locations 747 and
     748, and the number of characters in the output buffer to location
     749.

750,751        2EE,2EF        CBAUDL/H
     Cassette baud rate low and high bytes. Initialized to 1484
     ($5CC), which represents a nominal 600 baud (bits per second).
     After baud rate calculations, these locations will contain POKEY
     values for the corrected baud rate. The baud rate is adjusted by
     SIO to account for motor variations, tape stretch, etc. The
     beginning of every cassette record contains a pattern of
     alternating off/on bits (zero/one) which are used solely for speed
     (baud) correction.

752            2F0            CRSINH
     Cursor inhibit flag. Zero turns the cursor on; any other number
     turns the cursor off. A visible cursor is an inverse blank (space)
     character. Note that cursor visibility does not change until the
     next time the cursor moves (if changed during a program). If you
     wish to change the cursor status without altering the screen data,
     follow your CRSINH change with a cursor movement (i.e., up,
     down) sequence. This register is set to zero (cursor restored) on
     powerup, RESET, BREAK, or an OPEN command to either the
     display handler (S:) or screen editor (E:). See location 755 for
     another means to turn off the cursor.

753            2F1            KEYDEL
     Key delay flag or key debounce counter; used to see if any key
     has been pressed. If a zero is returned, then no key has been
     pressed. If three is returned, then any key. It is decremented
     every stage two VBLANK (1/60 or 1/30th second) until it reaches
     zero. If any key is pressed while KEYDEL is greater than zero, it
     is ignored as "bounce." See COMPUTE!, December 1981, for a
     routine to change the keyboard delay to suit your own typing
     needs.