mpc8250 Freescale Semiconductor, Inc, mpc8250 Datasheet - Page 23

• Manufacturer Part Number: mpc8250
• Description: Mpc8250 Powerquicc Ii Integrated Communications Processor
• Manufacturer: Freescale Semiconductor, Inc

3.2
The PCI mode is selected according to three input pins, as shown in
following:
Freescale Semiconductor
1
2
3
MODCK_H–MODCK[1–3]
is equal to or greater than 133 MHz (150 MHz for extended temperature parts) and the CPM ranges between 66–233
MHz.
resulting configuration does not exceed the frequency rating of the user’s part.
Input clock frequency is given only for the purpose of reference. User should set MODCK_H–MODCK_L so that the
Because of speed dependencies, not all of the possible configurations in
The user should choose the input clock frequency and the multiplication factors such that the frequency of the CPU
PCI Mode
1000_000
1000_001
1000_010
1000_100
0111_001
0111_010
0111_011
0111_100
0111_101
0111_110
1000_011
0111_111
In PCI mode only, PCI_MODCK comes from the LGPL5 pin and
MODCK_H[0–3] comes from {LGPL0, LGPL1, LGPL2, LGPL3}.
The minimum Tval = 2 when PCI_MODCK = 1, and the minimum Tval = 1
when PCI_MODCK = 0. Therefore, designers should use clock
configurations that fit this condition to achieve PCI-compliant AC timing.
Clock configurations change only after POR is asserted.
Table 14. Clock Configuration Modes
Frequency
Input Clock
66 MHz
66 MHz
66 MHz
66 MHz
66 MHz
66 MHz
66 MHz
66 MHz
66 MHz
66 MHz
66 MHz
66 MHz
MPC8250 Hardware Specifications, Rev. 1
2, 3
NOTE: Tval (Output Hold)
CPM Multiplication
NOTE: PCI_MODCK
Factor
3.5
3.5
3.5
3.5
3.5
3.5
3
3
3
3
3
3
NOTE
2
Frequency
200 MHz
200 MHz
200 MHz
200 MHz
200 MHz
200 MHz
233 MHz
233 MHz
233 MHz
233 MHz
233 MHz
233 MHz
CPM
1
(continued)
Table 14
Table
2
Core Multiplication
are applicable.
12. In addition, note the
Factor
2.5
3.5
4.5
2.5
3.5
4.5
2
3
4
2
3
4
2
Clock Configuration Modes
Frequency
133 MHz
166 MHz
200 MHz
233 MHz
266 MHz
300 MHz
133 MHz
166 MHz
200 MHz
233 MHz
266 MHz
300 MHz
Core
2
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