6845 Register Description - IBM 5150 Hardware Reference Manual

Table 6.
6845 Register Description
ADDR REG.
REGISTER
40x25 80x25
GRAPHIC
REG.
#
TYPE UNITS I/O ALPHA ALPHA
MODES
0 RO Horizontal
Char. Write 38 71 38
Total Only
1
R1 Horizontal Char. Write 28 50 28
Displayed
Only
2 R2 Horiz. Sync Char.
Write 20
5A 20
Position Only
3 R3 Horiz. Sync Char.
Write
OA
OA
OA
Width Only
4 R4 Vertical Total
Char. Write
1F 1F
7F
Row Only
5 R5 Vertical Total
Scan
Write
06 06 06
Adjust
Line
Only
6 R6 Vertical Char. Write 19 19 64
Displayed
Row Only
7 R7 Vert. Sync Char. Write 1C 1C
70
Position Row Only
8
R8
I
nterlace Mode
-
Write 02
02
02
Only
9 R9 Max Scan Scan Write 07
07 01
Line Addr. Line Only
A R10 Cursor Start Scan Write
06
06 06
Line Only
B
R11 Cursor End
Scan
Write 07 07 07
Line Only
C R12 Start Addr. (HI
-
Write 00
00 00
Only
0 R13 Start Addr. (Ll
-
Write 00 00
00
E R14 Cursor
-
Only
Read/
XX XX
XX
Addr. (HI Write
F
R15 Cursor
-
Read/
XX XX XX
Addr. (Ll Write
10 R16 Light Pen (HI
-
Read
XX
XX XX
Only
11 R17
Light Pen (Ll
-
Read
XX XX
XX
Only
Note: All register values are given in hexadecimal.
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