Chapter 3 Configuring the AI5TV
12
AI5TV Motherboard User’s Manual
SW1: AT Bus Clock Select
Use this DIP-Switch to select the frequency of the AT bus clock
(ATCLK). The ATCLK is derived from the PCI clock (PCLK) as
PCLK/3 or PCLK/4 and the PCLK is derived from the CPU clock
(CLK) as CLK/2.
For example, for a Pentium 100MHz system, the CLK would be
66MHz so the PCLK/2 equals to 33MHz. You would set SW1 as
PCLK/4 where ATCLK would be 8.3MHz.
SW1
AT Clock
OFF
PCI Clock/3
ON
PCI Clock/4 (Default setting)
SW2: CPU Voltage Select
SW2
JP25
CPU Type
Vcore
V
IO
ON
ON
Intel Pentium (P54C)
Cyrix 6x86, AMD K5
3.5V
3.5V
OFF
OFF
Intel Pentium MMX (P55C)
Cyrix 6x86L, AMD K6
2.8V
2.8V
SW3, SW5, SW6, SW7, SW8: CPU Frequency Select
For Intel CPUs
SW3 SW5 SW6 SW7 SW8
Bus
Clock
Multiplie
r
CPU
ON
OFF
OFF
ON
ON
50MHz
1.5x
P54C-75
ON
OFF
OFF
ON
OFF
60MHz
1.5x
P54C-90
ON
OFF
OFF
OFF
ON
66MHz
1.5x
P54C-100
ON
OFF
ON
ON
OFF
60MHz
2.0x
P54C-120
ON
OFF
ON
OFF
ON
66MHz
2.0x
P54C-133
ON
ON
ON
ON
OFF
60MHz
2.5x
P54C-150
ON
ON
ON
OFF
ON
66MHz
2.5x
P54C/P55C-166
ON
ON
OFF
OFF
ON
66MHz
3.0x
P54C/P55C- 200
ON
OFF
OFF
OFF
ON
66MHz
3.5x
P55C-233
