DEC VT220 Technical Manual page 104

300 H
2FF H
.....- - - -... 7FFH
BANK 3
CHARACTER
IA8=ll
IA9=1 A10=1j
I
- - - - -1700
H
BANK
3 6FF
H
ATTRIBUTE
(A8=Oi
I
(A9=1, A10=1) ,
-----,600H
BANK
2
Ii
5FF H
' I ' CHARACTER
(A8=1! "
IA9=0, A10=111
- _ _ - - 500H
BANK
2
4FF H
ATTRIBUTE
(AB=O)
IA9=0, A10=111
_ _ _ _ _ 400 H
I
BANK 1 , 3FF H
I
CHARACTER
(A8=11
,IA9=l, A10=01
BANK
1
ATTRIBUTE
n
(AB=O)
I
(A9=], A10=01
- - - - -1200 H
BANK 0 l1FF H
CHARACTER '
(AB=1)
IA9=0 A 10=0)
- - - - - 100 H
BANK
0
OFF H
ATTRiBUTE
t
(AB=OI '
I
(A9=O, A 1O=O)
I
! 1 000 H
Figure 6-15 Line Buffer RAM
Memory Map
FROM
B051 CPU
.i.:..~;";";";"';;;'"
FROM
SCREE'N
RAM4-
--J
FROM {SYNC OM'" H
TIMING T5l
GEN
------+----.....,,-Clr-........
FROM
ACCESS VIDEO LATCH H
MUX LBF DISABLE H
FROM
CPU LOGIC
FROM
ATTR IBUTE .L.;.;A..;;,D..;;,0_H;.,-_A;,;;D,;.7,;.H_ _...
RAM
CHAR
LATCH
1
TO
CHAR
OUTPUT
TO
LINE
BUFFER
TO
ATTRIBUTE
CIRCUITS
Figure 6-16
Data Input Buffers Block Diagram
6-20