6530 Programmer's Guide

Block Mode Operation
6530 Programmer’s Guide 3-37
Start Field (GS)
The GS control character (lDH) defines a new field. The start-field
address for the field is set to the current buffer address of the selected
page. If the current buffer address is equal to the start-field address of an
existing field, the attributes for that field are modified; otherwise, a new
field is created.
The GS character must be followed by two encoded ASCII characters that
specify the video and data attributes, respectively, for the field. These
attribute characters are ASCII characters in the range of 20H to 7FH,
whose binary value defines a bit pattern for the selected video and data
attributes. The video attribute character has the same bit pattern as
described for the Esc 6 video attribute character. The data attribute
character selects data attributes as follows:
For example, the following control sequence defines a new field with the
video attributes set to underscore and the data attributes set to unprotected
and numeric data only:
1DH 0T
You can set additional data attributes using the Start field extended
(Esc [ ) Sequence.
The data attributes for a field become operational when the cursor enters
the field. If a field is defined while the cursor is already positioned within
that field, the data attributes for that field will not be operational. An
exception to this is the protected attribute, which becomes operational as
soon as it is defined. Thus, you should make sure your application
program explicitly positions the cursor after the field is defined.
Bit 6543210
1 = MDT set
data type (0 - 7) (See Table 3-1.)
1 = auto-tab disable
0 = unprotected, 1 = protected
1