MPC8260A Motorola, MPC8260A Datasheet - Page 28

• Manufacturer Part Number: MPC8260A
• Description: Micro Processor
• Manufacturer: Motorola

Clock Configuration Modes
28
1
2
3
4
5
6
7
MODCK[1–3]
MODCK_H –
1100_000
1100_001
1100_010
1010_010
1010_011
1010_100
1011_000
1011_001
1011_010
1011_011
1011_100
The user should verify that all buses and functions run frequencies that are within the supported ranges.
The frequency depends on the value of PCI_MODCK. If PCI_MODCK is high (logic ‘1’), the PCI frequency
Input clock frequency is given only for the purpose of reference. User should set MODCK_H–MODCK_L so
Core frequency = (60x bus frequency)(core multiplication factor)
Bus frequency = CPM frequency / bus division factor
In this mode, PCI_MODCK must be “1”.
In this mode the Core PLL is bypassed (core frequency equals bus frequency; for debug purpose only).
is divided by 2 (33 instead of 66 MHz, etc.) and the CPM multiplication factor is multiplied by 2.
that the resulting configuration does not exceed the frequency rating of the user’s part.
Example. If a part is rated at 266 MHz CPU, 200 MHz CPM, and 66 MHz bus, any of the following are
possible (note that the three input clock frequencies are only three of many possible input clock
frequencies):
1. 50 MHz input clock, MODCK_H–MODCK_L[0110–011] (with a core multiplication factor of 4, a CPM
2. 66 MHz input clock, MODCK_H–MODCK_L[0100–001], and PCI_MODCK = 1 (see note 2 above) to
3. 40 MHz input clock, MODCK_H–MODCK_L[1001–011], and PCI_MODCK = 0 (see note 2 above) to
Note that with each of the examples, any one of several values for MODCK_H–MODCK_L could possibly
be used as long as the resulting configuration does not exceed the part’s rating.
multiplication factor of 4, and a bus division factor of 3), and PCI_MODCK = 0 (see note 2 above). The
PCI frequency is 50 MHz and the resulting configuration equals the part’s maximum possible frequencies
of 266 MHz CPU, 200 MHz CPM, and 66 MHz 60x bus.
achieve a PCI frequency of 33 MHz and a configuration of 200MHz CPU, 200 MHz CPM, and 66 MHz
60x bus.
achieve a PCI frequency of 40 MHz and a configuration of 160 MHz CPU, 160 MHz CPM, and 40 MHz
60x bus.
7
7
7
Input Clock
Frequency
66/33 MHz
66/33 MHz
66/33 MHz
66/33 MHz
66/33 MHz
66/33 MHz
66/33 MHz
66/33 MHz
Table 19. Clock Configuration Modes in PCI Agent Mode (Continued)
66/33MHz
66/33MHz
66/33MHz
(PCI)
2,3
PRELIMINARY—SUBJECT TO CHANGE WITHOUT NOTICE
MPC826xA (HiP4) Family Hardware Specifications
Multiplication
Factor
CPM
4/8
4/8
4/8
4/8
4/8
4/8
4/8
4/8
2/4
3/6
3/6
2
Frequency
266 MHz
266 MHz
266 MHz
266 MHz
266 MHz
266 MHz
266 MHz
266 MHz
133MHz
200MHz
200MHz
CPM
Multiplication
Bypass
Bypass
Bypass
Factor
Core
3.5
4.5
2.5
3.5
4
2
3
4
Frequency
300 MHz
350 MHz
400 MHz
265 MHz
318 MHz
371 MHz
424 MHz
212MHz
66MHz
80MHz
66MHz
Core
4
Bus Division
Factor
2.5
2.5
2.5
2.5
2.5
2.5
3
3
3
2
3
1
Frequency
MOTOROLA
106 MHz
106 MHz
106 MHz
106 MHz
106 MHz
60x Bus
88 MHz
88 MHz
88 MHz
66 MHz
80 MHz
66 MHz
5