MPC8270ZQT Просмотр технического описания (PDF) - Freescale Semiconductor
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MPC8270ZQT Datasheet PDF : 83 Pages
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Clock Configuration Modes
1 The “low” 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 Rev A or later the minimum CPU frequency is 150 MHz for commercial temperature devices
and 175 MHz for extended temperature devices.
2 MODCK_H = hard reset configuration word [28–31]. MODCK[1-3] = three hardware configuration pins.
3 60x and local bus frequency. Identical to CLKIN.
4 CPM multiplication factor = CPM clock/bus clock
5 CPU multiplication factor = Core PLL multiplication factor
7.2 PCI Host Mode
These tables show clock configurations for PCI host mode. The frequency values listed 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. Note that in PCI host mode the input clock is 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 ns when PCI_MODCK = 1, and the minimum
Tval = 1 ns when PCI_MODCK = 0. Therefore, designers should use clock
configurations that fit this condition to achieve PCI-compliant AC timing.
Table 19. Clock Configurations for PCI Host Mode (PCI_MODCK=0)1,2
Mode3
MODCK_H-
MODCK[1-3]
Bus Clock4
(MHz)
Low High
CPM
Multiplication
Factor5
CPM Clock
(MHz)
Low High
CPU
Multiplication
Factor6
CPU Clock
(MHz)
Low High
PCI
Division
Factor
PCI Clock
(MHz)
Low High
Default Modes (MODCK_H=0000)
0000_000 60.0 66.7
2
120.0 133.3
2.5
150.0 166.7
2
60.0 66.7
0000_001 50.0 66.7
2
100.0 133.3
3
150.0 200.0
2
50.0 66.7
0000_010 60.0 80.0
2.5
150.0 200.0
3
180.0 240.0
3
50.0 66.7
0000_011 60.0 80.0
2.5
150.0 200.0
3.5
210.0 280.0
3
50.0 66.7
0000_100 60.0 80.0
2.5
150.0 200.0
4
240.0 320.0
3
50.0 66.7
0000_101 50.0 66.7
3
150.0 200.0
3
150.0 200.0
3
50.0 66.7
0000_110 50.0 66.7
3.5
150.0 200.0
3.5
175.0 233.3
3
50.0 66.7
0000_111 50.0 66.7
3
150.0 200.0
4
200.0 266.6
3
50.0 66.7
Full Configuration Modes
0001_000 50.0 66.7
3
150.0 200.0
5
250.0 333.3
3
50.0 66.7
MPC8280 PowerQUICC II Family Hardware Specifications, Rev. 2
30
Freescale Semiconductor
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