6530 Programmer's Guide

Block Mode Operation
3-70
6530 Programmer’s Guide
Wraparound Fields
In EM3270 mode, 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. The following read command sequences
handle such a field by sending a DC1 command, followed first by a two
byte address, the data at the bottom of the screen, then data at the top of
the screen:
Esc < Read Whole Page
Esc = Read with Address
Esc ] Read with Address All
The video and data attributes of the last field on the screen are also
enforced for the positions at the top of the screen. This will effectively
override the Set Video Prior (Esc 7) setting.
The presence of such a field will have no impact on the Read All
Locations (Esc - n) command described below.
Read All Locations (Esc - n)
The Esc - n sequence reads all data and attributes on the screen. This
command transmits all characters on the screen including any null and
space characters. The Read All Locations command works in both
normal and EM3270 mode. In addition, for each attribute location the
following is transmitted:
GS video att data1 att data2 att
The DC1 row column is not sent for the attribute locations. A minimum
of 1920 bytes will be transmitted. The format of the escape sequence is
as follows:
Esc - n
The format of the reply from the terminal is as follows:
GS video att data1 att data2 att