TMP91C824
91C824-224
4.8
SCOUT Pin AC Characteristics
Variable
4 MHz
16 MHz
Symbol Parameter
Min Max
Min Max
Min Max
Condition Unit
0.5T
−
10
90 27 Vcc
≧
2.7 V
t
SCH
Low level Width
0.5T
−
30
70
-
Vcc
<
2.7 V
ns
0.5T
−
10
90
27
Vcc
≧
2.7 V
t
SCL
High level Width
0.5T
−
30
70
-
Vcc
<
2.7 V
ns
Note: T = Period of SCOUT
Measuring Conditions
!
Output Level: High = 0.7 V, Low = 0.3 V, CL
=
10 pF
4.9 Bus
Request/Bus
Acknowledge
BUSAK
A0 to A23,
RD , WR
CS0 to CS3 ,
W
/
R
,
HWR
ALE
AD0 to AD15
t
CBAL
t
ABA
t
BAA
(Note 2)
(Note 2)
(Note 1)
BUSRQ
Variable
f
FPH
=
4 MHz
f
FPH
=
16 MHz
Symbol Parameter
Min Max Min Max Min Max
Unit
t
ABA
Output Buffer Off to
BUSAK
Low
0 80 0 80 0 80
ns
t
BAA
BUSAK
High to Output Buffer On
0 80 0 80 0 80
ns
Note 1: Even if the
BUSRQ
Signal foes Low, the bus will not be released while the
WAIT
signal is Low.
The bus will only be released when
BUSRQ
goes Low while
WAIT
is High.
Note 2: This line shows only that the output buffer is in the off state.
It does not indicate that the signal level is fixed.
Just after the bus is released, the signal level set before the bus was released is maintained
dynamically by the external capacitance. Therefore, to fix the signal level using an external resister
during bus release, careful design is necessary, since fixing of the level is delayed.
The internal programmable pull-up/pull-down resistor is switched between the Active and
Non-Active states by the internal signal.