
45
AT/TSC8x251G2D
4135F–8051–11/06
AC Characteristics - Commercial & Industrial
AC Characteristics - External Bus Cycles
Definition of Symbols
Table 38.
External Bus Cycles Timing Symbol Definitions
Timings
Test conditions: capacitive load on all pins = 50 pF.
Table 39 and
Table 40 list the AC timing parameters for the TSC80251G2D derivatives
with no wait states. External wait states can be added by extending PSEN#/RD#/WR#
and or by extending ALE. In these tables, Note 2 marks parameters affected by one ALE
wait state, and Note 3 marks parameters affected by PSEN#/RD#/WR# wait states.
Signals
Conditions
A
Address
H
High
D
Data In
L
Low
L
ALE
V
Valid
Q
Data Out
X
No Longer Valid
R
RD#/PSEN#
Z
Floating
WWR#