Table of Contents
Advertisement
Bits
6 5
o
0
Zero character clock skew
o
lOne character clock skew
1 0
Two character clock skew
1 1
Three character clock skew
Start Address High Register
This is a read/write register pointed to when the value in the CRT
Controller address register is hex OC. The processor
input/ output port address for this register is hex 3B5 or hex 3D5.
Start Address High Register Format
Bit
7
6
5
4
3
2
1
0
I I I I I I I •
High Order Start Address
Bit O-Bit 7
Start Address High-These are the high-order
eight bits of the start address. The 16-bit value,
from the high-order and low-order start address
registers, is 'the first address after the vertical
retrace on each screen refresh.
Start Address Low Register
This is a read/write register pointed to when the value in the CRT
Controller address register is hex OD. The processor
input/ output port address for this register is hex 3B5 or hex 3D5.
Start Address Low Register Format
Bit
7
6
5
4
3
2
1
0
I I I
I •
Low Order Start Address
34 IBM Enhanced Graphics Adapter
Advertisement
Chapters
Table of Contents
