Intel IXP2800 and IXP2850 Network Processors
Electrical Specifications
100
Datasheet
4.4.2
Maximum Supported Operating Frequencies
Table 31 lists the maximum operating frequencies for the associated network processor
internal/external functional units. The maximum external interface operating frequencies are only
available using the 1.4 GHz parts.
Table 30. Clock Rates Examples
Input Oscillator Frequency (MHz)
100
PLL Output Frequency (MHz)
[PLL Multiplier]1
2000
[20]
2200
[22]
2400
[24]
2600
[26]
2800
[28]
4000
[40]
4800
[48]
Microengine Frequency2
1000
1100
1200
1300
1400
2000
2400
Intel XScale core & Command/Push/Pull
Bus Frequency 3
500
550
600
650
700
1000
1200
Divide Ratio for other Units
(except APB)4
Di
vi
sor
5
26
500
550
600
650
700
1000
1200
3
333
367
400
433
467
666
800
4
250
275
300
325
350
500
600
5
200
220
240
260
280
400
480
6
167
183
200
217
233
334
400
7
143
157
171
186
200
286
342
8
125
138
150
163
175
250
300
9
111
122
133
144
156
222
266
10
100
110
120
130
140
200
240
11
91
100
109
118
127
182
218
12
83
92
100
108
117
166
200
13
77
85
92
100
107
154
184
14
71
79
86
93
100
142
172
15
67
73
80
87
93
134
160
1. This multiplier is selected via SP_AD[5:0] strap pins.
2. This frequency is the PLL output frequency divided by 2.
3. This frequency is the PLL output frequency divided by 4.
4. The ABP divisor specified in the CLOCK_CONTROL CAP CSR is scaled by an additional x4.
5. This divisor is selected via the CLOCK_CONTROL CAP CSR. Base Frequency is the PLL output frequency divided by 2.
6. This divide ratio is only used by test logic. In the normal functional mode, this ratio is reserved for Push/Pull clocks only.
Table 31. Maximum Supported Operating Frequencies
Device
Microengine
Frequency
QDR
Frequency
RDR1
Frequency
1. The minimum supported frequency for the RDR interface is 400 MHz.
MSF2,3
Frequency
2. Derived from an external source.
3. The minimum supported frequency for the MSF interface is 200 MHz.
PCI Frequency
RPIXP2800BB
1.4 GHz
233 MHz4
4. These frequencies cannot be achieved simultaneously with a 1.4 GHz Microengine operating frequency.
500 MHz
66 MHz
RPIXP2800BA
1.0 GHz
200 MHz
400 MHz
66 MHz
RPIXP2800BC
650 MHz
163 MHz
432 MHz
400 MHz
66 MHz
RPIXP2850BB
1.4 GHz
233 MHz
533 MHz
500 MHz
66 MHz
RPIXP2850BA
1.0 GHz
200 MHz
400 MHz
66 MHz
RPIXP2850BC
650 MHz
163 MHz
432 MHz
400 MHz
66 MHz