HD66740 Datasheet, PDF (31/95 Pages) Hitachi Semiconductor – 112 x 80-dot Graphics LCD Controller/Driver

HD66740
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.
R/W RS DB7 DB6 DB5 DB4 DB3 DB2 DB1 DB0
1 1 RD7 RD6 RD5 RD4 RD3 RD2 RD1 RD0
Figure 14 Read Data from RAM Instruction
Address: N set
Start byte
First byte Dummy read (invalid data)
Address: N set
Second byte Read (data of address N)
Start byte
Address: N±1 (RDM = 0)
Address: N (RDM = 1)
i) Parallel bus interface mode
First byte Dummy read (invalid data)
Second byte Dummy read (invalid data)
Third byte Read (data of address N)
Address: N±1 (RDM = 0)
Address: N (RDM = 1)
ii) Serial interface mode
Figure 15 RAM Read Sequence
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