6530 Programmer's Guide

Block Mode Operation
6530 Programmer’s Guide 3-45
Read with Address (Esc =)
The Esc = sequence reads a specified area of the selected page by using
normal addressing format described in “Cursor and Buffer Addressing”
on page 3-13. The format for the escape sequence is:
Esc = start-row start-column end-row end-column
where:
start-row and start-column are encoded ASCII characters
that specify the beginning location of the area to be read (read start
address).
end-row and end-column are encoded ASCII characters that
specify the ending location of the area to be read (read end address).
For example, the following sequence reads an area starting at row 5,
column 5 and ending at row 10, column 10:
1BH = $ $ ) )
If the read end address is less than the read start address, an empty block
is transmitted.
In nonprotect submode, the 6530 transmits the entire area specified by the
read start address and read end address (inclusive).
In protect submode, the 6530 transmits data only from fields that have
their MDTs set and are within the specified area as described in “Fields
and Field Attributes (Protect Submode)” on page 3-1.
Notes Both unprotected and protected fields within the specified area are
transmitted if these fields have their MDTs set. If no fields within the
area have their MDTs set, an empty block is transmitted.
In EM3270 mode, this sequence:
Stores nulls rather than spaces in the screen buffer.
A screen with no fields is treated as a single unformatted field. Data
may be keyed at any character position. This escape sequence
handles such a screen by transmitting any character position not
containing a null. These data are not preceded by a DC1 row column
sequence.
If there is no attribute at row 1, column 1, the last field on the screen
wraps around to include any characters preceding the first attribute
location on the screen. This command sequence handles such a field
by sending a DC1 command, followed first by a two byte address, then
the data at the bottom of the screen, and the data at the top of the
screen.