AMD SC1201, SC1200 manual 2 GX1 Module Core Clock, Internal Fast-PCI Clock, Core Clock Frequency

General Configuration Block 32579B

4.5.2GX1 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.

4.5.3Internal 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.)

Table 4-6. Core Clock Frequency

ADL	Internal Fast-PCI Clock Freq. (MHz)
Multiplier
Value	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

	Internal Fast-PCI Clock	Default ADL Multiplier
CLKSEL[3:0]	Freq. (MHz)		Multiplier Value	Maximum Core
Straps	(GCB+I/O Offset 1Eh[9:8])	Multiply By	(GCB+I/O Offset 1Eh[3:0])	Clock Freq. (MHz)
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

Note: Not all speeds are supported. For information on supported speeds, see Section A.1 "Order Information" on page 441.

AMD Geode™ SC1200/SC1201 Processor Data Book 85