AC Parameters
Each timing symbol has 5 characters. The first character is always a “T” (stands for
time). The other characters, depending on their positions, stand for the name of a signal
or the logical status of that signal. The following is a list of all the characters and what
they stand for.
Example:
T
T
AVLL = Time for Address Valid to ALE Low.
LLPL = Time for ALE Low to PSEN Low.
TA = -55°C to +125°C (Military temperature range); VSS = 0V; VCC = 5V 10%;
Load capacitance for Port 0, ALE and PSEN = 100 pF; Load capacitance for all other
outputs = 80 pF.
Table 4. External Program Memory Characteristics (ns)
30 MHz
Symbol
TLHLL
TAVLL
TLLAX
TLLIV
Parameter
Min Max
ALE Pulse Width
60
15
35
100
25
80
65
0
Address Valid to ALE
Address Hold After ALE
ALE to Valid Instruction In
ALE to PSEN
TLLPL
TPLPH
TPLIV
PSEN Pulse Width
PSEN to Valid Instruction In
Input Instruction Hold After PSEN
Input Instruction Float After PSEN
PSEN to Address Valid
Address to Valid Instruction In
PSEN Low to Address Float
TPXIX
TPXIZ
TPXAV
TAVIV
30
35
130
6
TPLAZ
Figure 7. External Program Memory Read Cycle
12 TCLCL
TLHLL
TLLIV
TLLPL
ALE
PSEN
TPLPH
TPXAV
TPXIZ
TLLAX
TAVLL
TPLIV
TPLAZ
TPXIX
INSTR IN
PORT 0
PORT 2
INSTR IN
A0-A7
A0-A7
INSTR IN
TAVIV
ADDRESS A8-A15
ADDRESS
OR SFR-P2
ADDRESS A8-A15
12
80C32E
4149M–AERO–06/03
AIMTEC [ AIMTEC ]
