MPC8280 PowerQUICC II Family Hardware Specifications, Rev. 1.8
Freescale Semiconductor
41
Clock Configuration Modes
1100_111
25.0
50.0
6
150.0 300.0
5
250.0 500.0
3
50.0
100.0
1101_000
25.0
50.0
6
150.0 300.0
5.5
275.0 550.0
3
50.0
100.0
1101_001
25.0
50.0
6
150.0 300.0
3.5
210.0 420.0
2.5
60.0
120.0
1101_010
25.0
50.0
6
150.0 300.0
4
240.0 480.0
2.5
60.0
120.0
1101_011
25.0
50.0
6
150.0 300.0
4.5
270.0 540.0
2.5
60.0
120.0
1101_100
25.0
50.0
6
150.0 300.0
5
300.0 600.0
2.5
60.0
120.0
1110_000
25.0
50.0
5
125.0 250.0
2.5
156.3 312.5
2
62.5
125.0
1110_001
25.0
50.0
5
125.0 250.0
3
187.5 375.0
2
62.5
125.0
1110_010
25.0
50.0
5
125.0 250.0
3.5
218.8 437.5
2
62.5
125.0
1110_011
25.0
50.0
5
125.0 250.0
4
250.0 500.0
2
62.5
125.0
1110_100
25.0
50.0
5
125.0 250.0
4
166.7 333.3
3
41.7
83.3
1110_101
25.0
50.0
5
125.0 250.0
4.5
187.5 375.0
3
41.7
83.3
1110_110
25.0
50.0
5
125.0 250.0
5
208.3 416.7
3
41.7
83.3
1110_111
25.0
50.0
5
125.0 250.0
5.5
229.2 458.3
3
41.7
83.3
1100_000
Reserved
1100_001
Reserved
1100_010
Reserved
1
The “l(fā)ow” values are the minimum allowable frequencies for a given clock mode. The minimum bus frequency in a table entry
guarantees only the required minimum CPU operating frequency. The “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 violate the frequency rating of
the user’s device. The minimum CPM frequency is 120 MHz. Minimum CPU frequency is determined by the clock mode. For
modes with a CPU multiplication factor <= 3, the minimum CPU frequency is 150 MHz for commercial temperature devices
and 175 MHz for extended temperature devices. For modes with a CPU multiplication factor >= 3.5: for Rev0.1 the minimum
CPU frequency is 250 MHz; for RevA or later the minimum CPU frequency is 150 MHz for commercial temperature devices
and 175 MHz for extended temperature devices.
2
As shown in
Table 15, PCI_MODCK determines the PCI clock range. Refer to
Table 19 for higher range configurations.
3
MODCK_H = hard reset configuration word [28–31]. MODCK[1-3] = three hardware configuration pins.
4
CPM multiplication factor = CPM clock/PCI clock
5
CPU multiplication factor = Core PLL multiplication factor
Table 20. Clock Configurations for PCI Agent Mode (PCI_MODCK=1) 1, 2 (continued)
Mode 3
PCI Clock
(MHz)
CPM
Multiplication
Factor 4
CPM Clock
(MHz)
CPU
Multiplication
Factor 5
CPU Clock
(MHz)
Bus
Division
Factor
Bus Clock
(MHz)
MODCK_H-
MODCK[1-3]
Low
High
Low
High
Low
High
Low
High