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AMD Geode™ SC2200 Processor Data Book
91
General Configuration Block
32580B
4.5.7
Clock Registers
Table 4-9 describes the registers of the clock generator and PLL.
Table 4-8. Clock Generator Configuration
Bit
Description
Offset 10h
Maximum Core Clock Multiplier Register - MCCM (RO)
Reset Value: Strapped Value
This register holds the maximum core clock multiplier value. The maximum clock frequency allowed by the core, is the Fast-PCI clock
multiplied by this value.
7:4
Reserved.
3:0
MCM (Maximum Clock Multiplier).
This 4-bit value is the maximum multiplier value allowed for the core clock generator. It
is derived from strap pins CLKSEL[3:0] based on the multiplier value in Table 4-7 on page 89.
Offset 11h
Reserved - RSVD
Offset 12h
PLL Power Control Register - PPCR (R/W)
Reset Value: 2Fh
This register controls operation of the PLLs.
7
Reserved.
6
EXPCID (Disable External PCI Clock).
0: External PCI clock is enabled.
1: External PCI clock is disabled.
5
GPD (Disable Graphic Pixel Reference Clock).
0: PLL2 input clock is enabled.
1: PLL2 input clock is disabled.
4
Reserved.
3
PLL3SD (Shut Down PLL3).
AC97 codec clock.
0: PLL3 is enabled.
1: PLL3 is shutdown.
2
FM1SD (Shut Down PLL4).
0: PLL4 is enabled.
1: PLL4 is shutdown, unless internal Fast-PCI clock is strapped to 48 MHz.
1
C48MD (Disable SuperI/O and USB Clock).
0: USB and SuperI/O clock is enabled.
1: USB and SuperI/O clock is disabled.
0
Reserved.
Write as read.
Offset 13h-17h
Reserved - RSVD
Offset 18h-1Bh
PLL3 Configuration Register - PLL3C (R/W)
Reset Value: E1040005h
31:24
MFFC (MFF Counter Value).
Fvco
= OSCCLK * MFBC / (MFFC * MOC)
OSCCLK = 27 MHz
23:19
Reserved.
Write as read.
18:8
MFBC (MFB Counter Value).
Fvco
= OSCCLK * MFBC / (MFFC * MOC)
OSCCLK = 27 MHz
Note:
Bits 18, 9, and 8 cannot be changed. Bit 18 is always a 1; bits 9 and 8 are always 0.
7
Reserved.
Write as read.
6
Reserved.
Must be set to 0.
5:0
MOC (MO Counter Value).
Fvco
= OSCCLK * MFBC / (MFFC * MOC)
OSCCLK = 27 MHz
Offset 1Eh-1Fh
Core Clock Frequency Control Register - CCFC (R/W)
Reset Value: Strapped Value
This register controls the configuration of the core clock multiplier and the reference clocks.
Содержание Geode SC2200
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Страница 70: ...74 AMD Geode SC2200 Processor Data Book Signal Definitions 32580B...
Страница 350: ...366 AMD Geode SC2200 Processor Data Book Debugging and Monitoring 32580B...
Страница 422: ...440 AMD Geode SC2200 Processor Data Book Electrical Specifications 32580B...
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