hd66740 Renesas Electronics Corporation., hd66740 Datasheet - Page 31

• Manufacturer Part Number: hd66740
• Description: 112 X 80-dot Graphics Lcd Controller/driver - Hitachi Semiconductor
• Manufacturer: Renesas Electronics Corporation.

Read Data from RAM
RD7-0 : Read 8-bit data from the CGRAM. In the parallel bus interface mode, the first-byte data read will
be invalid immediately after the RAM address set, and the consecutive second-byte data will be read
normally. In the serial interface mode or I2C bus interface mode, two bytes will be invalid immediately
after the start byte, and the consecutive third-byte data will be read normally. For details, see the Serial
Data Transfer section.
After a RAM read, when RDM = 0, the address is automatically incremented or decremented by 1
according to the I/D bit. When RDM = 1, the address is not updated.
Second byte
First byte
i) Parallel bus interface mode
Dummy read (invalid data)
Address: N 1 (RDM = 0)
Address: N (RDM = 1)
Read (data of address N)
Address: N set
R/W RS DB7
1
Figure 14
1
Figure 15
RD7 RD6 RD5 RD4 RD3 RD2 RD1 RD0
Read Data from RAM Instruction
DB6 DB5 DB4 DB3 DB2 DB1
RAM Read Sequence
31
Second byte
Third byte
First byte
Dummy read (invalid data)
Dummy read (invalid data)
Address: N 1 (RDM = 0)
Address: N (RDM = 1)
Read (data of address N)
ii) Serial interface mode
DB0
Address: N set
Start byte
Start byte
HD66740