IBM RT Series Hardware Reference Manual page 405

The following is a block diagram of the monochrome display
adapter portion of the IBM Monochrome Display and Printer
Adapter.
Processor
Address
Processor
Data
AO
Chip
Select
Timing
Signals
(12) ..
Memory
...
Address
(1~
Multiplexer
Data
..
""
Bus
Gating
BOO-7
J
(8)
MA
. .
...
..
...
MC6845
..
CRTC
""
..
r
-
(10)
2K Memory
Character
Code
(8)
...
row
..
(8)
row
Character
"
Clock
Octal
t...
1
_
..
Latch
...
-
...
~
RA ..
Character
(4)
...
Generator
DOTCLK
Shift
...
..
Register '"
...
Serial Dots
..
...
HSYNC, VSYNC, CURSOR, DISPEN ...
...
Character
Clock
(10)
2K Memory
Attribute
4~
"
Octal
Latch
Attribute
Decode
I
Video
Process
Logic
+
Monitor
Direct Drive
Outputs
IBM Monochrome Display Adapter Block Diagram
Monochrome Adapter 3