Appendix A Electrical Characteristics
668
MC9S12C-Family / MC9S12GC-Family
Freescale Semiconductor
Rev 01.24
Figure A-3. Jitter Definitions
The relative deviation of t
nom
is at its maximum for one clock period, and decreases towards zero for larger
number of clock periods (N).
Defining the jitter as:
For N < 100, the following equation is a good fit for the maximum jitter:
Figure A-4. Maximum Bus Clock Jitter Approximation
This is very important to notice with respect to timers, serial modules where a pre-scaler will eliminate the
effect of the jitter to a large extent.
2
3
N-1
N
1
0
t
nom
t
max1
t
min1
t
maxN
t
minN
J N
( )
max 1
t
max
N
( )
N t
nom
⋅
---------------------
–
1
t
min
N
( )
N t
nom
⋅
---------------------
–
,
⎝
⎠
⎜
⎟
⎛
⎞
=
J N
( )
j
1
N
--------
j
2
+
=
1
5
10
20
N
J(N)
Summary of Contents for MC9S12C Family
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