9-10
MPC8260 PowerQUICC II UserÕs Manual
MOTOROLA
Part III. The Hardware Interface
The relationships among these parameters are described in the formulas in Figure 9-5.
Figure 9-5. Relationships of SCMR Parameters
9.10 Basic Power Structure
The I/O buffers, logic, and clock block are fed by a 3.3-V power supply that allows them to
function in a TTL-compatible voltage range. Internal logic can be fed by a 2.0-V source
considerably reducing power consumption. The PLL is fed by a separate power supply
(VCCSYN) to achieve a highly stable output frequency. The VCCSYN value is equal to the
internal supply (2.0 V).
The MPC8260 supports the two following power modes:
¥
Full mode: Both the chip PLL and core PLL work.
¥
Stop mode: Main PLL is working, core PLL is stopped, internal clocks are disabled.
Ñ When stop mode is entered, software sets the sleep bit in the core (HID0[10] =
1) and the clock block freezes all clocks to the chip (the core clock and all other
clocks) the main PLL remains active
Ñ When stop mode is exited, the SRESET_B input must be asserted to the chip, the
clock block resumes clocks to all blocks and then releases the reset to the whole
chip.
19
PLLDF
ConÞg pins
Unaffected
PLL pre-divider value. Ensures that PLLMF is an integer value
regardless of whether CPM_CLK/CLKIN is an integer.
0 The ratio, CPM_CLK/CLKIN, is an integer
1 The ratio, CPM_CLK/CLKIN, is not an integer
PLL division factor can be either 1 or 2.
20Ð31
PLLMF
ConÞg pins
Unaffected
PLL multiplication factor. (A PLLMF value of 0x000 corresponds to 1,
and 0xFFF to 4,096.) The VCO output is divided to generate the
feedback signal that goes to the phase comparator. PLLMF and
PLLDF bits control the value of the divider in the PLL feedback loop.
The phase comparator determines the phase shift between the
feedback signal and the reference clock. This difference causes an
increase or decrease in the VCO output frequency.
Table 9-5. SCMR Field Descriptions (Continued)
Bits
Name
Defaults
Description
POR
Hard Reset
PLLMF = CPM_CLK
CLKIN
´
(PLLDF + 1) Ð 1
BUSDF = (PLLMF + 1)
´
2
(PLLDF + 1)
Ð 1
Summary of Contents for MPC8260 PowerQUICC II
Page 1: ...MPC8260UM D 4 1999 Rev 0 MPC8260 PowerQUICC II UserÕs Manual ª ª ...
Page 66: ...lxvi MPC8260 PowerQUICC II UserÕs Manual MOTOROLA ...
Page 88: ...1 18 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA Part I Overview ...
Page 120: ...2 32 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA Part I Overview ...
Page 138: ...Part II iv MPC8260 PowerQUICC II UserÕs Manual MOTOROLA Part II Configuration and Reset ...
Page 184: ...4 46 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA Part II ConÞguration and Reset ...
Page 202: ...Part III vi MPC8260 PowerQUICC II UserÕs Manual MOTOROLA Part III The Hardware Interface ...
Page 266: ...8 34 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA Part III The Hardware Interface ...
Page 382: ...10 106 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA Part III The Hardware Interface ...
Page 392: ...11 10 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA Part III The Hardware Interface ...
Page 430: ...Part IV viii MOTOROLA Part IV Communications Processor Module ...
Page 490: ...14 36 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA Part IV Communications Processor Module ...
Page 524: ...17 10 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA Part IV Communications Processor Module ...
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Page 980: ...A 4 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA Appendixes ...
Page 1002: ...Index 22 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA INDEX ...
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