MOTOROLA
Appendix B. Serial Communications Performance
B-5
Appendixes
IDMA will be treated as a Ôbackground task,Õ and will only be serviced when other channels
do not require service, and will thus not interfere with them.
If IDMA is conÞgured to be a higher-priority task, then its transfers must be considered
when calculating demands on the CPM bandwidth. Table B-2 provides performance
information for the IDMA channels in their different modes. Its use is similar to the table
provided for the serial channels (Table B-1).
B.3.3 Performance Calculations
Special conÞgurations veriÞed by experiment.
The performance Þgures quoted in Table B-1 can be used to estimate the overall CPM
bandwidth required in a particular system conÞguration. To calculate the total system load,
add the CPM utilization from every channel together. Assuming approximately linear
performance versus frequency, the general problem reduces to taking simple ratios:
For example, since a 25-MHz MPC860 running Ethernet (theoretically) at 22 Mbps
consumes approximately 100% of the CPM bandwidth, what bandwidth does a (practical)
10-Mbps channel require?
The above equation shows the 10-Mbps channel requiring 45% of the CPM bandwidth of
a 25 MHz MPC860.
Table B-2. IDMA Performance at 25 MHz
Protocol Speed
IDMA Memory to Memory
5.7 MByte/s
IDMA Mem to Mem with Burst Aligned Source/Dest Addr
10.4 MByte/s
IDMA Dual Address, Peripheral to Memory
2.2 MByte/s
IDMA Dual Address, Memory to Peripheral
1.6 MByte/s
IDMA Single Address, Peripheral to Memory
5 MByte/s
IDMA Single Address, Memory to Peripheral
5 MByte/s
Note:
1.Performance scales linearly with device operating frequency
2.IDMA transfer rates are independent of bus cycle length
CPM Utilization
serial rate
1
max serial rate
1
-------------------------------------
è
ø
æ
ö
serial rate
2
max serial rate
2
-------------------------------------
è
ø
æ
ö
¼
+
=
CPM Utilization
serial rate
max serial rate
-----------------------------------
10
22
------
0.45
=
=
=
Summary of Contents for MPC860 PowerQUICC
Page 3: ...MPC860UM AD 07 98 REV 1 MPC860 PowerQUICC ª UserÕs Manual ...
Page 36: ...xxxvi MPC860 PowerQUICC UserÕs Manual MOTOROLA CONTENTS Paragraph Number Title Page Number ...
Page 78: ...I iv MPC860 PowerQUICC UserÕs Manual MOTOROLA Part I Overview ...
Page 88: ...1 10 MPC860 PowerQUICC UserÕs Manual MOTOROLA Part I Overview ...
Page 114: ...3 16 MPC860 PowerQUICC UserÕs Manual MOTOROLA Part I Overview ...
Page 226: ...8 32 MPC860 PowerQUICC UserÕs Manual MOTOROLA Part II PowerPC Microprocessor Module ...
Page 262: ...9 36 MPC860 PowerQUICC UserÕs Manual MOTOROLA Part II PowerPC Microprocessor Module ...
Page 274: ...III iv MPC860 PowerQUICC UserÕs Manual MOTOROLA Part III Configuration ...
Page 320: ...12 12 MPC860 PowerQUICC UserÕs Manual MOTOROLA Part III Configuration ...
Page 325: ...MOTOROLA Part IV Hardware Interface IV v Part IV Hardware Interface ...
Page 326: ...IV vi MPC860 PowerQUICC UserÕs Manual MOTOROLA Part IV Hardware Interface ...
Page 352: ...13 26 MPC860 PowerQUICC UserÕs Manual MOTOROLA Part IV Hardware Interface ...
Page 394: ...14 42 MPC860 PowerQUICC UserÕs Manual MOTOROLA Part IV Hardware Interface ...
Page 426: ...15 32 MPC860 PowerQUICC UserÕs Manual MOTOROLA Part IV Hardware Interface ...
Page 530: ...17 26 MPC860 PowerQUICC UserÕs Manual MOTOROLA Part IV Hardware Interface ...
Page 632: ...21 44 MPC860 PowerQUICC UserÕs Manual MOTOROLA Part V The Communications Processor Module ...
Page 660: ...22 28 MPC860 PowerQUICC UserÕs Manual MOTOROLA Part V The Communications Processor Module ...
Page 708: ...24 24 MPC860 PowerQUICC UserÕs Manual MOTOROLA Part V The Communications Processor Module ...
Page 748: ...27 20 MPC860 PowerQUICC UserÕs Manual MOTOROLA Part V The Communications Processor Module ...
Page 846: ...31 20 MPC860 PowerQUICC UserÕs Manual MOTOROLA Part V The Communications Processor Module ...
Page 914: ...35 12 MPC860 PowerQUICC UserÕs Manual MOTOROLA Part V The Communications Processor Module ...
Page 948: ...36 34 MPC860 PowerQUICC UserÕs Manual MOTOROLA Part V The Communications Processor Module ...
Page 998: ...37 48 MPC860 PowerQUICC UserÕs Manual MOTOROLA Part VI Debug and Test ...
Page 1016: ...A 10 MPC860 PowerQUICC UserÕs Manual MOTOROLA Appendixes ...
Page 1024: ...B 8 MPC860 PowerQUICC UserÕs Manual MOTOROLA Appendixes ...
Page 1030: ...C 6 MPC860 PowerQUICC UserÕs Manual MOTOROLA Appendixes ...
Page 1086: ...Glossary 12 MPC860 PowerQUICC UserÕs Manual MOTOROLA ...
Page 1106: ......