W83194R-58A Datasheet, PDF (7/13 Pages) Winbond – 100MHZ AGP CLOCK FOR VIA CHIPSET

W83194R-58A
PRELIMINARY
8.3 SERIAL CONTROL REGISTERS
The Pin column lists the affected pin number and the @PowerUp column gives the state at true
power up. Registers are set to the values shown only on true power up. "Command Code" byte and
"Byte Count" byte must be sent following the acknowledge of the Address Byte. Although the data
(bits) in these two bytes are considered "don't care", they must be sent and will be acknowledge.
After that, the below described sequence (Register 0, Register 1, Register 2, ....) will be valid and
acknowledged.
8.3.1 Register 0: CPU Frequency Select Register
Bit @PowerUp
7
0
6
0
5
0
4
0
3
0
2
0
1
0
0
0
Pin
Description
-
0 = ±0.25% Spread Spectrum Modulation
1 = ±0.5% Spread Spectrum Modulation(W83194R-58)
-
SSEL2 ( Frequency table selection by software via I²C)
-
SSEL1 ( Frequency table selection by software via I²C)
-
SSEL0 ( Frequency table selection by software via I²C)
-
0 = Selection by hardware
1 = Selection by software I²C - Bit 6:4
-
SSEL3 (Frequency table selection by software via I²C for
W83194R-58)
-
0 = Normal
1 = Spread Spectrum enabled
-
0 = Running
1 = Tristate all outputs
Publication Release Date: Nov. 1999
-7-
Revision 0.30