MPC8250ACVVMHBC Просмотр технического описания (PDF) - Freescale Semiconductor
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MPC8250ACVVMHBC Datasheet PDF : 62 Pages
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Clock Configuration Modes
Table 14. Clock Configuration Modes 1 (continued)
MODCK_H–MODCK[1–3]
Input Clock
Frequency2,3
CPM Multiplication
Factor2
CPM Core Multiplication
Frequency2
Factor2
Core
Frequency2
0111_001
0111_010
0111_011
0111_100
0111_101
0111_110
66 MHz
66 MHz
66 MHz
66 MHz
66 MHz
66 MHz
3
200 MHz
2
133 MHz
3
200 MHz
2.5
166 MHz
3
200 MHz
3
200 MHz
3
200 MHz
3.5
233 MHz
3
200 MHz
4
266 MHz
3
200 MHz
4.5
300 MHz
0111_111
66 MHz
3.5
233 MHz
2
133 MHz
1000_000
66 MHz
3.5
233 MHz
2.5
166 MHz
1000_001
66 MHz
3.5
233 MHz
3
200 MHz
1000_010
66 MHz
3.5
233 MHz
3.5
233 MHz
1000_011
66 MHz
3.5
233 MHz
4
266 MHz
1000_100
66 MHz
3.5
233 MHz
4.5
300 MHz
1 Because of speed dependencies, not all of the possible configurations in Table 14 are applicable.
2 The user should choose the input clock frequency and the multiplication factors such that the frequency of the CPU
is equal to or greater than 133 MHz (150 MHz for extended temperature parts) and the CPM ranges between 66–233
MHz.
3 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.
3.2 PCI Mode
The PCI mode is selected according to three input pins, as shown in Table 12. In addition, note the
following:
NOTE: PCI_MODCK
In PCI mode only, PCI_MODCK comes from the LGPL5 pin and
MODCK_H[0–3] comes from {LGPL0, LGPL1, LGPL2, LGPL3}.
NOTE: Tval (Output Hold)
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.
NOTE
Clock configurations change only after POR is asserted.
MPC8250 Hardware Specifications, Rev. 2
Freescale Semiconductor
23
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