AMD Geode SC1201 - Manual (Page 85)

AMD Geode™ SC1200/SC1201 Processor Data Book 85
General Configuration Block 32579B
4.5.2 GX1 Module Core Clock
The core clock is generated by an Analog Delay Loop
(ADL) clock generator from the internal Fast-PCI clock. The
clock can be any whole number multiple of the input clock
between 4 and 10. Possible values are listed in Table 4-6.
At power-on reset, the core clock multiplier value is set
according to the value of four strapped balls - CLKSEL[3:0]
(balls P30, D29, AF3, B8). These balls also select the clock
which is used as input to the multiplier, as shown in Table
4-7.
4.5.3 Internal Fast-PCI Clock
The internal Fast-PCI clock can be configured to 33, 48, or
66 MHz via strap options on the CLKSEL1 and CLKSEL0
balls. These can be read in the internal Fast-PCI Clock field
in the CCFC register (GCB+I/O Offset 1Eh[9:8]). (See
Table 4-8 on page 87 details on the CCFC register.)
Note: Not all speeds are supported. For information on supported speeds, see Section A.1 "Order Information" on page
441.
Table 4-6. Core Clock Frequency
ADL
Multiplier
Value
Internal Fast-PCI Clock Freq. (MHz)
33.33 48 66.67
4 133.3 192 266.7
5 166.7 240 ---
6 200 288 ---
7 233.3 --- ---
8 266.7 --- ---
9 --- --- ---
10 --- --- ---
Table 4-7. Strapped Core Clock Frequency
CLKSEL[3:0]
Straps
Internal Fast-PCI Clock
Freq. (MHz)
(GCB+I/O Offset 1Eh[9:8])
Default ADL Multiplier
Maximum Core
Clock Freq. (MHz) Multiply By
Multiplier Value
(GCB+I/O Offset 1Eh[3:0])
0111 33.33 4 0100 133
1011 5 0101 167
1111 6 0110 200
0000 7 0111 233
0100 8 1000 266
1000 9 1001 Reserved
1100 10 1010 Reserved
0001 48 4 0100 192
0101 5 0101 240
1001 6 0110 288
1101 7 0111 Reserved
0110 66.67 4 0100 266
1010 5 0101 Reserved