Bit
Number
Function
0
+
High Resolution Mode
1
Not Used
2
Not Used
3
+
Video Enable
4
Not Use:d
5
+
Enable Blink
6,7
Not Used
6845 CRT Control Port 1 (Hex 3B8)
Bit
Number
Function
0
+
Horizontal Drive
1
Reserved
2
Reserved
3
+
Black/White Video
6845 CRT Status Port (Hex 3BA)
8 Monochrome Adapter