MPC8270 MOTOROLA [Motorola, Inc], MPC8270 Datasheet - Page 30

• Manufacturer Part Number: MPC8270
• Description: PowerQUICC II Family Hardware Specifications
• Manufacturer: MOTOROLA [Motorola, Inc]

1
2
3
4
5
6
MODCK[1-3]
MODCK_H-
MODCK[1-3]
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As Table 14 shows, PCI_MODCK determines the PCI clock frequency range. Refer to Table 17 for lower configurations.
MODCK_H = hard reset configuration word [28–31]. MODCK[1-3] = three hardware configuration pins.
60x and local bus frequency. Identical to CLKIN.
CPM multiplication factor = CPM clock/bus clock
CPU multiplication factor = Core PLL multiplication factor
0000_000
0000_001
0000_010
0000_011
0000_100
MODCK_H-
“Low” values are the minimum allowable frequencies for a given clock mode. The minimum bus frequency guarantees
the required minimum CPU operating frequency. Minimum CPU frequency is determined by the clock mode.
For modes with a CPU multiplication factor ≤ 3, the minimum CPU frequency is 166 MHz. The minimum CPM frequency
is 133 MHz.
For modes with a CPU multiplication factor ≥ 3.5, the minimum CPU frequency is 250 MHz. The minimum CPM
frequency is as shown in the table.
“High” values are for the purpose of illustration only. Users must select a mode and input bus frequency so that the
resulting configuration does not exceed the frequency rating of the user’s device.
1101_101
1101_110
1110_000
1110_001
1110_010
1110_011
1110_100
1100_000
1100_001
1100_010
Mode
Mode
3
3
Table 16. Clock Configurations for PCI Host Mode (PCI_MODCK=0)
Bus Clock
66.7
66.7
60.0
71.4
62.5
low
125.0 166.7
125.0 166.7
100.0 133.3
100.0 133.3
100.0 133.3
100.0 133.3
100.0 133.3
Bus Clock
low
Table 17. Clock Configurations for PCI Host Mode (PCI_MODCK=1)
(MHz)
(MHz)
100.0
100.0
120.0
120.0
120.0
high
high
MPC8280 PowerQUICC II™ Family Hardware Specifications
4
4
Multiplication
Multiplication
Factor
Factor
CPM
CPM
2.5
2.5
2.5
2
2
2
2
3
3
3
3
3
5
5
Default Modes (MODCK_H=0000)
250.0 333.3
250.0 333.3
300.0 400.0
300.0 400.0
300.0 400.0
300.0 400.0
300.0 400.0
133.3 200.0
133.3 200.0
150.0 300.0
178.6 300.0
156.3 300.0
CPM Clock
CPM Clock
low
low
(MHz)
(MHz)
high
high
Multiplication
Multiplication
Reserved
Reserved
Reserved
Factor
Factor
CPU
CPU
2.5
3.5
3.5
4.5
5.5
3
3
4
3
4
4
5
6
6
375.0 500.0
500.0 666.6
350.0 466.6
400.0 533.3
450.0 599.9
500.0 666.6
550.0 733.3
166.7 250.0
200.0 300.0
180.0 360.0
250.0 420.0
250.0 480.0
CPU Clock
CPU Clock
low
low
(MHz)
(MHz)
high
high
1,2
(Continued)
Division
Division
Factor
Factor
PCI
1,2
PCI
5
5
6
6
6
6
6
4
4
6
6
6
MOTOROLA
PCI Clock
50.0 66.7
50.0 66.7
50.0 66.7
50.0 66.7
50.0 66.7
50.0 66.7
50.0 66.7
low high
33.3 50.0
33.3 50.0
25.0 50.0
29.8 50.0
26.0 50.0
PCI Clock
low high
(MHz)
(MHz)