SSD1812

22

REV 1.2

12/99

SOLOMON

Data Read / Write

To read data from the GDDRAM, input High to R/W(WR) pin and D/C pin for 6800-series parallel mode, Low to E(RD) pin and High to D/

C pin for 8080-series parallel mode. No data read is provided for serial mode. In normal mode, GDDRAM column address pointer will be

increased by one automatically after each data read. However, no automatic increase will be performed in read-modify-write mode. Also, a

dummy read is required before the first data read. See Figure 4 in Functional Description.

To write data to the GDDRAM, input Low to R/W(WR) pin and High to D/C pin for 6800-series parallel mode. For serial interface, it will

always be in write mode. GDDRAM column address pointer will be increased by one automatically after each data write.

Address Increment Table (Automatic)

Remarks:

*1. If read data is issued in read-modify-write mode, address increase is not applied.

*2. Column Address will NOT wrap round when overflow.

Commands Required for R/W(WR) Actions on RAM

* No need to resend the command again if it is set previously.

The read / write action to the Display Data RAM does not depend on the display mode. This means the user can change the RAM content

whether the target RAM content is being displayed or not.

Bit Pattern

Read Command

(D/C=0, R/W(WR)=1, E(RD)=0)

Comment

(Data Read Back from the

driver)

Status Register Read

used to identify as Solomon Systech Device.

D/C

R/W(WR) Comment

Address Increment

Remarks

0

0

Write Command

No

0

1

Read Status

No

1

0

Write Data

Yes

1

1

Read Data

Yes

*1

R/W(WR) Actions on RAMs

Commands Required

Read/Write Data from/to GDDRAM.

Set GDDRAM Page Address

Set GDDRAM Column Address

Read/Write Data

Save/Restore GDDRAM Column Address.

Save GDDRAM Column Address by read-modify-

write mode

Restore GDDRAM Column Address by end of read-

modify-write mode

(11100000)

(11101110)