**CIGAL Reference Manual, Chapter 4 (Variables): tablet**
===== Tablet -- Integer variable controlling digitizing tablet settings =====
**usage:  tablet = value**

TABLET, an internally defined integer variable, controls how you can use a
digitizing tablet to move the cursor.  The value of the TABLET parameter can
be changed at any time and remains set until it is explicitly modified again.

Note: In order to actually use the tablet to control the cursor you must set two
other flags in addition to TABLET.  You must set the appropriate flag in the
CURSOR control variable (see [[jvs:cigal:manual:chapter4:cursor|CURSOR(4)]]), and also set the properties of the I/O
port by assigning an appropriate value to the line control variable COM1 or COM2
(see [[jvs:cigal:manual:chapter4:com1|COM1(4)]] or [[biac:jvs:cigal:manual:chapter4:COM2|COM2(4)]]).

The TABLET variable has several bit-fields with different meanings. The 2
lowest bits specify to which communication port the digitizing tablet is
attached.  The next 10 bits indicate what format your tablet uses to send
its positional data.  This can be either ASCII or binary coded.  If it's
ASCII, then the YKKNNNNN fields (see below) should be used to specify the
format.  If it's binary then CIGAL will only accept data if the tablet
format is one of those in the list recognized by the TT field. You set
TABLET by adding the various bit fields.

Details of the bit-fields in the 16-bit TABLET variable are as follows:
                         mfssttykknnnnncc
  
                     Tablet Parameters   Communication port
                                    # ASCII Chars
   Select:         Field: Bits:  Value: Meaning:
  
   Communications  CC     0-1      0    COM1 - 1st asynchronous, serial port
    port                           1    COM2 - 2nd asynchronous, serial port
                                 2-3    Undefined
   Num. of chars   nnnnn  2-6   0-31    Number of ASCII characters, excluding
    of ASCII data                       CR or LF (i.e. ASCII values >= 32)
   Key value flag  kk     7-8      0    No Key code; X and Y only
                                   1    Key first; then X and Y
                                   2    X and Y first; then Key
                                   3    undefined
   XY order        y      9        0    X value first; then Y
                                   1    Y value first; then X
   Tablet type     tt     10-11    1    Summagraphics BitPad (binary format)
                                 2-3    undefined
   Shift factor    ss     12-13  0-3    Shift X/Y values SS bits to right
                                         (i.e., divide by 2 ** ss)
   Y flip          f      14       1    Flip Y coord. (y = ymax - y)
   Minus flag      m      15       1    Negative values accepted (ASCII only)

**See Also:**\\
[[jvs:cigal:manual:chapter4:cursor|CURSOR(4)]]

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