HD44780U Datasheet, PDF (32/59 Pages) Hitachi Semiconductor – Dot Matrix Liquid Crystal Display Controller/Driver

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Interfacing the HD44780U
Interface to MPUs
• Interfacing to an 8-bit MPU
See Figure 16 for an example of using a I/O port (for a single-chip microcomputer) as an interface
device.
In this example, P30 to P37 are connected to the data bus DB0 to DB7, and P75 to P77 are connected to
E, R/W, and RS, respectively.
RS
R/W
E
Internal
operation
DB7
Data
Instruction
write
Functioning
Busy
Busy flag
check
Busy
Busy flag
check
Not
busy
Busy flag
check
Data
Instruction
write
Figure 15 Example of Busy Flag Check Timing Sequence
H8/325
P30 to P37
P77
P76
P75
HD44780U
8
COM1 to ¹⁶
DB0 to DB7 _COM16
LCD
E
RS
SEG1 to ⁴⁰
R/W
SEG40
Figure 16 H8/325 Interface (Single-Chip Mode)
32