Rainbow Electronics HD44780 - Manual (Page 49)

HD44780U
49
AC Characteristics (V
CC
= 2.7 to 4.5 V, T
a
= –30 to +75
°
C* 3 )
Clock Characteristics
Item Symbol Min Typ Max Unit Test Condition Note*
External External clock frequency f
cp
125 250 350 kHz 11
clock
External clock duty Duty 45 50 55 %
operation
External clock rise time t
rcp
— — 0.2
µ
s
External clock fall time t
fcp
— — 0.2
µ
s
R
f
oscillation
Clock oscillation frequency f
OSC
190 270 350 kHz R
f
= 75 k
Ω
,
V
CC
= 3 V
12
Note: * Refer to the Electrical Characteristics Notes section following these tables.
Bus Timing Characteristics
Write Operation
Item Symbol Min Typ Max Unit Test Condition
Enable cycle time t
cycE
1000 — — ns Figure 25
Enable pulse width (high level) PW
EH
450 — —
Enable rise/fall time t
Er
, t
Ef
— — 25
Address set-up time (RS, R/ W to E) t
AS
60 — —
Address hold time t
AH
20 — —
Data set-up time t
DSW
195 — —
Data hold time t
H
10 — —
Read Operation
Item Symbol Min Typ Max Unit Test Condition
Enable cycle time t
cycE
1000 — — ns Figure 26
Enable pulse width (high level) PW
EH
450 — —
Enable rise/fall time t
Er
, t
Ef
— — 25
Address set-up time (RS, R/ W to E) t
AS
60 — —
Address hold time t
AH
20 — —
Data delay time t
DDR
— — 360
Data hold time t
DHR
5 — —