8

AmC0XXDFLKA

Table 2.

Attribute Memory Bus Operations

Notes:

1. X indicates any value.

3. During Attribute Memory Read function, REG and OE must be active for the entire cycle.

4. Only even-byte data is valid during Attribute Memory Read function.

5. During Attribute Memory Write function, REG and WE must be active for the entire cycle, OE must be inactive for the

entire cycle.

6. The first 128 bytes of the attribute memory is not writable as it contains the CIS. Only the remaining 384 bytes are writable.

Pins/Operation

REG

CE2CE1OE

WE

A0

D8–D15

D0–D7

READ/WRITE

Read Mode (Note 3)

Standby Mode

X

H

H

X

X

X

High-Z

High-Z

Word Access (Note 4)

LLLL

H

X

Not Valid

Data Out-Even

Even Byte Access

L

H

L

L

H

L

High-Z

Data Out-Even

Odd Byte Access (Note 4)

L

H

L

L

H

H

High-Z

Not Valid

Odd-Byte-Only Access (Note 4)

L

LHLH

X

Not Valid

High-Z

Write Mode (Note 5,6)

Standby Mode

X

H

H

X

X

X

X

X

Word Access

L

L

L

H

L

X

X

Data In-Even

Low Byte Access

LHLHL

L

X

Data In-Even

Odd Byte Access

LHLHLH

X

X

Odd-Byte-Only Access

L

L

H

X

H

L

X

X

Output Disable

L

X

X

H

H

X

High-Z

High-Z