AT89C51ID2-SMSIM ATMEL [ATMEL Corporation], AT89C51ID2-SMSIM Datasheet - Page 143

• Manufacturer Part Number: AT89C51ID2-SMSIM
• Description: 8-bit Flash Microcontroller
• Manufacturer: ATMEL [ATMEL Corporation]

External Program Memory
Characteristics
4289A–8051–09/03
Table 98, Table 99 and Table 105 give the frequency derating formula of the AC param-
eter for each speed range description. To calculate each AC symbols. take the x value
in the correponding column (-M or -L) and use this value in the formula.
Example: T
x = 35 ns
T 50 ns
T
Table 97. Symbol Description
Table 98. AC Parameters for a Fix Clock
CCIV
Symbol
T
T
T
T
T
T
T
T
T
T
T
PLPH
PLAZ
LHLL
AVLL
LLAX
LLPL
PLIV
PXIX
PXIZ
AVIV
LLIV
T
= 4T - x = 165 ns
Symbol
T
T
T
T
T
T
T
T
T
T
T
PLPH
AVLL
LLAX
PLAZ
LHLL
LLPL
PXIX
PXIZ
AVIV
LLIV
PLIV
T
LLIU
for -M and 20 MHz, Standard clock.
Parameter
Oscillator clock period
ALE pulse width
Address Valid to ALE
Address Hold After ALE
ALE to Valid Instruction In
ALE to PSEN
PSEN Pulse Width
PSEN to Valid Instruction In
Input Instruction Hold After PSEN
Input Instruction Float After PSEN
Address to Valid Instruction In
PSEN Low to Address Float
Min
25
35
50
5
5
5
0
-M
Max
n 65
30
10
80
10
Min
25
35
50
5
5
5
0
AT89C51ID2
-L
Max
65
30
10
80
10
Units
143
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns