Platform Clock Routing Guidelines
R
Intel
®
Pentium
®
4 Processor / Intel
®
850 Chipset Family Platform Design Guide 47
4.2.2 133 MHz Operation – Intel
®
82850E Chipset
The BCLK[1:0] frequency should be set for 133 MHz operation for the 82850E chipset. This is
accomplished with a 1 kΩ pull-up to VCC3_CLK on the CK-00 SEL100/133 input. The correct
frequency select circuitry is show in the Figure below.
Figure 17. BCLK [1:0] Frequency Select for 133 MHz System Bus Operation
RDRAM
Sys Bus Freq/2
(50MHz or
66MHz)
BSEL0 (133/100)
MULT0 MULT1
CK00 Clock Chip
ICH
DMCG
CPU
GPOx
GPOx
GPI
1K ohm
VCC3_CLK
SEL100/133
REFCLK
3VMREF_B
BSEL1
No Connect