MC9S12HZ128VAL Datasheet, PDF (646/692 Pages) Freescale Semiconductor, Inc – MC9S12HZ256 Data Sheet, Rev. 2.05

Appendix A Electrical Characteristics
0
1
2
3
N–1
N
t_min1
t_nom
t_max1
t_minN
t_maxN
Figure A-4. 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_
J(N) = max_

as:
1–
t-N-_{m-----⋅a---tx-n--}(_--o-N--m--)_-
,
1
–
N-t--^m---⋅^-i--nt--_n^-(--_o^-N---_m^-)-



For N < 100, the following equation is a good fit for the maximum jitter:
J(N)
=
---^j--¹---
N
+
j₂
J(N)
15
10
20
N
Figure A-5. 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.
MC9S12HZ256 Data Sheet, Rev. 2.05
646
Freescale Semiconductor