DEC VT220 Technical Manual page 214

ADDRESS 17C1 H (WR)
07 06 05 04 03 02
01 00
(BAD7 HI ..
4t-------------------....
(BADO HI
BIT VALUES
BIT 0-7
4FH
OR
B3H
BINARY DEFINITiON OF NUMBER OF CHARACTER
TIMES PER DATA ROW LESS ONE 14FH FOR
BO COLUMN, OR B3H FOR 132 COLUMNI,
NOTE
THIS REGISTER VALUE SUBTRACTED FROM
CHARACTERS PER HORIZONTAL RETRACE
REGISTER VALUE DEFINES CHARACTER TIMES
IN HORIZONTAL RETRACE PERIOD
Figure C-15
9007 VPAC: Characters Per
Data Row Register
ADDRESS
07
06
, 7C2H (WR)
05 04 03 02
01
00
(BAD7 HI ....
t --------------------l.....
(BADO HI
BIT VALUES
BIT 0-7
xx
BINARY DEFINITION OF NUMBER OF CHARACTER
TIMES FROM LEADING EDGE OF HORIZ SYNC L
TO LEADING EDGE OF VLT H,
Figure C-16 9007 VPAC: Horizontal Sync
Delay Register
C-ll