Datasheet

MPC8250 Hardware Specifications, Rev. 2
26 Freescale Semiconductor
Clock Configuration Modes
3.2.2 PCI Agent Mode
The frequencies listed in Table 17 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.
1001_001 66 MHz 3.5 233 MHz 3 200 MHz 4/8 58/29 MHz
1001_010 66 MHz 3.5 233 MHz 3.5 233 MHz 4/8 58/29 MHz
1001_011 66 MHz 3.5 233 MHz 4 266 MHz 4/8 58/29 MHz
1001_100 66 MHz 3.5 233 MHz 4.5 300 MHz 4/8 58/29 MHz
1010_000 100 MHz 2 200 MHz 2 200 MHz 3/6 66/33 MHz
1010_001 100 MHz 2 200 MHz 2.5 250 MHz 3/6 66/33 MHz
1010_010 100 MHz 2 200 MHz 3 300 MHz 3/6 66/33 MHz
1010_011 100 MHz 2 200 MHz 3.5 350 MHz 3/6 66/33 MHz
1010_100 100 MHz 2 200 MHz 4 400 MHz 3/6 66/33 MHz
1011_000 100 MHz 2.5 250 MHz 2 200 MHz 4/8 62/31 MHz
1011_001 100 MHz 2.5 250 MHz 2.5 250 MHz 4/8 62/31MHz
1011_010 100 MHz 2.5 250 MHz 3 300 MHz 4/8 62/31 MHz
1011_011 100 MHz 2.5 250 MHz 3.5 350 MHz 4/8 62/31 MHz
1011_100 100 MHz 2.5 250 MHz 4 400 MHz 4/8 62/31 MHz
1
Input clock frequency is given only for the purpose of reference. User should set MODCK_H–MODCK_L so that
the resulting configuration does not exceed the frequency rating of the user’s part.
2
The frequency depends on the value of PCI_MODCK. If PCI_MODCK is high (logic ‘1’), the PCI frequency is
divided by 2 (33 instead of 66 MHz, etc.). Refer to Table 12
3
In this mode, PCI_MODCK must be “0”.
Table 17. Clock Default Configurations in PCI Agent Mode (MODCK_HI = 0000)
MODCK[1–3]
1
Input Clock
Frequency
(PCI)
2
CPM
Multiplication
Factor
2
CPM
Frequency
Core
Multiplication
Factor
Core
Frequency
3
Bus Division
Factor
60x Bus
Frequency
4
000 66/33 MHz 2/4 133 MHz 2.5 166 MHz 2 66 MHz
001 66/33 MHz 2/4 133 MHz 3 200 MHz 2 66 MHz
010 66/33 MHz 3/6 200 MHz 3 200 MHz 3 66 MHz
011 66/33 MHz 3/6 200 MHz 4 266 MHz 3 66 MHz
Table 16. Clock Configuration Modes in PCI Host Mode (continued)
MODCK_H
–
MODCK[1–
3]
Input Clock
Frequency
1
(Bus)
CPM
Multiplication
Factor
CPM
Frequency
Core
Multiplication
Factor
Core
Frequency
PCI Division
Factor
2
PCI
Frequency
2