HD66724 Datasheet, PDF (51/117 Pages) Hitachi Semiconductor – (Graphics LCD Controller/Driver with Key Scan Function)

HD66724/HD66725
Read Data from RAM
RD7-0 : Reads the 8-bit data from DDRAM, CGRAM or SEGRAM. DDRAM/CGRAM/SEGRAM is
selected by the previous specification of the RM 1/0 bit. In the parallel bus interface mode, the first-byte
data read will be invalid immediately after the RAM address is set, and the subsequent second-byte data
will be read normally. In the serial interface mode, two bytes will be invalid immediately after the start
byte, and the subsequent third-byte data will be read normally. For details, see the Serial Data Transfer
section. After a DDRAM read, the address is automatically incremented or decremented by 1 according to
the I/D bit setting in the entry mode set instruction.
R/W RS DB7 DB6 DB5 DB4 DB3 DB2 DB1 DB0
1 1 RD7 RD6 RD5 RD4 RD3 RD2 RD1 RD0
Figure 23 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
i) Parallel bus interface mode
First byte Dummy read (invalid data)
Second byte Dummy read (invalid data)
Third byte Read (data of address N)
ii) Serial interface mode
Figure 24 RAM Read Sequence
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