
Electrical Characteristics
Expansion Bus Timing Characteristics
MC68HC11E Family
—
Rev. 4
Technical Data
MOTOROLA
Electrical Characteristics
243
26
Delay time, E to AS rise
t
ASD
= 1/8 t
cyc
–
9.5 ns
(2) (3)a
t
ASD
115.5
—
53
—
31
—
ns
27
Pulse width, AS high
PW
ASH
= 1/4 t
cyc
–
29 ns
(2)
PW
ASH
221
—
96
—
63
—
ns
28
Delay time, AS to E rise
t
ASED
= 1/8 t
cyc
–
9.5 ns
(2) (3)b
t
ASED
115.5
—
53
—
31
—
ns
29
MPU address access time
(3)a
t
ACCA
= t
cyc
–
(PW
EL
–
t
AVM
)
–
t
DSR
–
t
f
t
ACCA
744.5
—
307
—
196
—
ns
35
MPU access time
t
ACCE
= PW
EH
–
t
DSR
t
ACCE
—
442
—
192
111
ns
36
Multiplexed address delay
(Previous cycle MPU read)
t
MAD
= t
ASD
+ 30 ns
(2) (3)a
t
MAD
145.5
—
83
—
51
—
ns
1. V
DD
= 5.0 Vdc
±
10%, V
SS
= 0 Vdc, T
A
= T
L
to T
H
, all timing is shown with respect to 20% V
DD
and 70% V
DD
, unless
otherwise noted
2. Formula only for dc to 2 MHz
3. Input clocks with duty cycles other than 50% affect bus performance. Timing parameters affected by input clock duty cycle
are identified by (a) and (b). To recalculate the approximate bus timing values, substitute the following expressions in place
of 1/8 t
cyc
in the above formulas, where applicable:
(a) (1
–
dc)
×
1/4 t
cyc
(b) dc
×
1/4 t
cyc
Where:
dc is the decimal value of duty cycle percentage (high time)
Num
Characteristic
(1)
Symbol
1.0 MHz
2.0 MHz
3.0 MHz
Unit
Min
Max
Min
Max
Min
Max