HD66789 Datasheet, PDF (28/156 Pages) Renesas Technology Corp – 528-channel, One-chip Driver for Amorphous TFT Panels with 262,144-color display RAM, Power Supply Circuit, and Gate Circuit

HD66789
Preliminary
Instructions
Outline
The HD66789 adapts 18-bit bus architecture that enables high-speed interfacing with a high-performance
microcomputer. Data sent from external (18/16/9/8 bits) are stored temporarily in the instruction register
(IR) and the data register (DR) to store control information before internal operation starts. Since internal
operation is decided according to the signal sent from the microcomputer, register selection signal (RS),
read/write signal (R/W), and internal 16-bit data bus signal (DB15 to DB0) are called instruction. GRAM
is accessed through internal 18-bit data bus. There are eight categories of instructions:
1. Specify index
2. Read status
3. Control display
4. Control power management
5. Process graphics data
6. Set internal GRAM address
7. Transfer data to and from internal GRAM
8. Set grayscale level for internal grayscale γ-adjustment
Normally, the 7^th instruction to write display data is executed the most frequently. The address of internal
GRAM is updated automatically after data are written to the internal GRAM. With the window address
function, this reduces the amount of data transmission to minimum and thereby lightens the load on the
program in the microcomputer. Since instructions are executed in 0 cycle, it is possible to write
instructions consecutively.
As the following figure shows, the assignment to the 16 instruction bits (IB15-0) varies according to the
interface in use. An instruction must adopt the data format for each interface.
Rev.0.12, May 09 2003, page 28 of 156