B-6
MPC860 PowerQUICC UserÕs Manual
MOTOROLA
Appendixes
A spreadsheet tool for performing serial performance calculations has been developed and
is available on the world-wide web site at http://www.mot.com/netcomm. It is entitled
ÒCPM Performance SpreadsheetÓ, and is located in the EngineerÕs Toolbox.
Please note that CPM load estimation is a linear approximation to a somewhat nonlinear
phenomenon, and cannot be relied upon to be exact. When performance estimations
approach the maximum loading (i.e. greater than approximately 95%), the user should test
the system on target hardware to determine the exact load. Conversely, some system
conÞgurations that calculate to greater than 100% by these equations have been veriÞed by
experiment. These include:
¥
A 25 MHz MPC860MH with one half-duplex Ethernet and 24 QMC channels (i.e.
24 x 64 kbps QMC) [if and only if SCC1 is Ethernet and QMC channels are spread
over two SCCs, e.g. SCC1=Ethernet, SCC2=QMC channels 0-11, SCC3=QMC
channels 12-23].
¥
A 33 MHz MPC860MH with one half-duplex Ethernet and 32 QMC channels (i.e.
32 x 64 kbps QMC) [if and only if SCC1 is Ethernet QMC channels are spread over
two SCCs, e.g. SCC1=Ethernet, SCC2=QMC channels 0-15, SCC3=QMC channels
16-31].
¥
A 40 MHz MPC860EN with four half-duplex Ethernet channels.
More examples of CPM bandwidth calculations follow:
Example #1:
MPC860 (at 25 MHz) operating 1
´
10 Mbps Ethernet in half duplex, 1
´
2 Mbps HDLC,
1
´
64 Kbps HDLC, 1
´
9.6 Kbps UART and 1
´
38 Kbps SMC UART. The following
equation applies:
This yields a percentage CPM utilization of 89% meaning the device can handle these
protocols at this frequency. Note the 9.6-Kbps UART link only requires 0.4% of the CPM
bandwidth, implying that in any conÞguration where there is free bandwidth that it will be
possible to run a low-rate UART link.
Example #2:
MPC860MH (at 25 MHz) running 24 QMC channels with an additional 2 HDLC channels
operating at 128 Kbps each. The following equation applies:
10
22
------
è ø
æ ö
2
8
---
è ø
æ ö
0.064
2.4
-------------
è
ø
æ
ö
0.0096
2.4
----------------
è
ø
æ
ö
0.038
0.22
-------------
è
ø
æ
ö
+
+
+
+
0.89 ( <1)
=
2
0.128
´
8
----------------------
è
ø
æ
ö
24
0.064
´
2.1
-------------------------
è
ø
æ
ö
+
0.76 ( <1)
=
Содержание MPC860 PowerQUICC
Страница 3: ...MPC860UM AD 07 98 REV 1 MPC860 PowerQUICC ª UserÕs Manual ...
Страница 36: ...xxxvi MPC860 PowerQUICC UserÕs Manual MOTOROLA CONTENTS Paragraph Number Title Page Number ...
Страница 78: ...I iv MPC860 PowerQUICC UserÕs Manual MOTOROLA Part I Overview ...
Страница 88: ...1 10 MPC860 PowerQUICC UserÕs Manual MOTOROLA Part I Overview ...
Страница 114: ...3 16 MPC860 PowerQUICC UserÕs Manual MOTOROLA Part I Overview ...
Страница 226: ...8 32 MPC860 PowerQUICC UserÕs Manual MOTOROLA Part II PowerPC Microprocessor Module ...
Страница 262: ...9 36 MPC860 PowerQUICC UserÕs Manual MOTOROLA Part II PowerPC Microprocessor Module ...
Страница 274: ...III iv MPC860 PowerQUICC UserÕs Manual MOTOROLA Part III Configuration ...
Страница 320: ...12 12 MPC860 PowerQUICC UserÕs Manual MOTOROLA Part III Configuration ...
Страница 325: ...MOTOROLA Part IV Hardware Interface IV v Part IV Hardware Interface ...
Страница 326: ...IV vi MPC860 PowerQUICC UserÕs Manual MOTOROLA Part IV Hardware Interface ...
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Страница 632: ...21 44 MPC860 PowerQUICC UserÕs Manual MOTOROLA Part V The Communications Processor Module ...
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Страница 998: ...37 48 MPC860 PowerQUICC UserÕs Manual MOTOROLA Part VI Debug and Test ...
Страница 1016: ...A 10 MPC860 PowerQUICC UserÕs Manual MOTOROLA Appendixes ...
Страница 1024: ...B 8 MPC860 PowerQUICC UserÕs Manual MOTOROLA Appendixes ...
Страница 1030: ...C 6 MPC860 PowerQUICC UserÕs Manual MOTOROLA Appendixes ...
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