HD66727 Datasheet, PDF (40/97 Pages) Hitachi Semiconductor – Low-Power Dot-Matrix Liquid Crystal Display Controller/Driver with Key Scan Function

HD66727
IRE: When IRE is 1, the key scan interrupt (IRQ*) generation is enabled. When a key is pressed, the IRQ*
pin outputs a low level signal.
KF1, KF0: Used for specifying the key scan cycle. Set these bits according to the mechanical
characteristics of the keys and the oscillation frequency (Table 22).
Table 22 KF Bits and Key Scan Cycles
NL1
KF1
KF0
Key Scan Cycle
1 or 2 display lines (NL1=0)
0
0
160/fosc
1 or 2 display lines (NL1=0)
0
1
320/fosc
1 or 2 display lines (NL1=0)
1
0
640/fosc
1 or 2 display lines (NL1=0)
1
1
1,280/fosc
3 or 4 display lines (NL1=1)
0
0
320/fosc
3 or 4 display lines (NL1=1)
0
1
640/fosc
3 or 4 display lines (NL1=1)
1
0
1,280/fosc
3 or 4 display lines (NL1=1)
1
1
2,560/fosc
Note: fosc is the oscillation frequency or external clock frequency.
Key Strobe Width
20/fosc
40/fosc
80/fosc
160/fosc
40/fosc
80/fosc
160/fosc
320/fosc
40