
41
TS8xCx2X2
4184I–8051–02/08
eter. To calculate each AC symbols, take the x value corresponding to the speed grade
you need (-M, -V or -L) and replace this value in the formula. Values of the frequency
must be limited to the corresponding speed grade:
Table 25. Max frequency for derating formula regarding the speed grade
Example:
TLLIV in X2 mode for a -V part at 20 MHz (T = 1/20E6 = 50 ns):
T= 50ns
TLLIV= 2T - x = 2 x 50 - 22 = 78ns
External Program Memory
Characteristics
Table 26. Symbol Description
-M X1 mode
-M X2 mode
-V X1 mode
-V X2 mode
-L X1 mode
-L X2 mode
Freq (MHz)
40
20
40
30
20
T (ns)
25
50
25
33.3
50
Symbol
Parameter
T
Oscillator clock period
TLHLL
ALE pulse width
TAVLL
Address Valid to ALE
TLLAX
Address Hold After ALE
TLLIV
ALE to Valid Instruction In
TLLPL
ALE to PSEN
TPLPH
PSEN Pulse Width
TPLIV
PSEN to Valid Instruction In
TPXIX
Input Instruction Hold After PSEN
TPXIZ
Input Instruction FloatAfter PSEN
TPXAV
PSEN to Address Valid
TAVIV
Address to Valid Instruction In
TPLAZ
PSEN Low to Address Float