MPC8248 Freescale Semiconductor, Inc, MPC8248 Datasheet - Page 33

• Manufacturer Part Number: MPC8248
• Description: Mpc8248 Powerquicc Ii Integrated Communications Processor
• Manufacturer: Freescale Semiconductor, Inc

7.2
Table 18
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. Note that in PCI agent mode the
input clock is PCI clock.
Freescale Semiconductor
1
2
3
4
5
MODCK[1-3]
MODCK[1-3]
MODCK_H-
MODCK_H-
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
exceed the frequency rating of the user’s device. The minimum CPU frequency is 150 MHz for commercial
temperature devices and 175 MHz for extended temperature devices. The minimum CPM frequency is 120 MHz.
MODCK[1-3] = three hardware configuration pins.
1110_100
1100_000
1100_001
1100_010
The “low” values are the minimum allowable frequencies for a given clock mode. The minimum bus frequency in a
PCI_MODCK determines the PCI clock frequency range. Refer to
MODCK_H = hard reset configuration word [28–31] (refer to Section 5.4 in the MPC8260 User’s Manual ).
CPM multiplication factor = CPM clock/bus clock
CPU multiplication factor = Core PLL multiplication factor
0000_000
0000_001
0000_010
0000_011
0000_100
0000_101
0000_110
Mode
Mode
and
PCI Agent Mode
Table 17. Clock Configurations for PCI Host Mode (PCI_MODCK=1)
3
3
Table 19
Table 18. Clock Configurations for PCI Agent Mode (PCI_MODCK=0)
Low
50.0 100.0
Low
60.0
50.0
50.0
50.0
50.0
50.0
50.0
Bus Clock
PCI Clock
(MHz)
(MHz)
MPC8272 PowerQUICC II™ Family Hardware Specifications, Rev. 1.5
show configurations for PCI agent mode. The frequency values listed are for the
High
High
66.7
66.7
66.7
66.7
66.7
66.7
66.7
Multiplication
Multiplication
Factor
Factor
CPM
CPM
3
2
2
3
3
3
3
4
Default Modes (MODCK_H=0000)
4
4
150.0 300.0
120.0 133.3
100.0 133.3
150.0 200.0
150.0 200.0
150.0 200.0
150.0 200.0
200.0 266.6
CPM Clock
Low
CPM Clock
Low
(MHz)
(MHz)
High
High
Reserved
Reserved
Reserved
Multiplication
Multiplication
Factor
Factor
CPU
CPU
5.5
2.5
3.5
3.5
Table 16
3
3
4
3
5
5
for higher range configurations.
275.0 550.0
150.0 166.7
150.0 200.0
150.0 200.0
200.0 266.6
180.0 240.0
210.0 280.0
233.3 311.1
CPU Clock
Low
CPU Clock
Low
(MHz)
(MHz)
High
High
1, 2
Division
Division
(continued)
Factor
Factor
Bus
PCI
Clock Configuration Modes
2.5
2.5
6
2
2
3
3
3
1, 2
Low
25.0
Low
60.0
50.0
50.0
50.0
60.0
60.0
66.7
Bus Clock
PCI Clock
(MHz)
(MHz)
High
High
50.0
66.7
66.7
66.7
66.7
80.0
80.0
88.9
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