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參數(shù)資料
| 型號： | CY28378 |
| 廠商： | Cypress Semiconductor Corp. |
| 英文描述： | FTG for Pentium 4 and Intel 845 Series Chipset |
| 中文描述： | 為奔騰4和Intel 845系列芯片組FTG |
| 文件頁數(shù)： | 11/22頁 |
| 文件大?。?/td> | 174K |
| 代理商： | CY28378 |
CY28378
Document #: 38-07519 Rev. **
Page 11 of 22
Program the CPU output frequency
When the programmable output frequency feature is enabled
(Pro_Freq_EN bit is set), the CPU output frequency is deter-
mined by the following equation:
Fcpu = G * N/M.
“N” and “M” are the values programmed in Programmable
Frequency Select N-Value Register and M-Value Register,
respectively.
Table 6. Examples of N and M Value for Different CPU Frequency Range
“G” stands for the PLL Gear Constant, which is determined by
the programmed value of FS[4:0] or SEL[4:0]. The value is
listed in
Table 2
.
The ratio of N and M need to be greater than “1” [N/M> 1].
The following table lists set of N and M values for different
frequency output ranges. This example use a fixed value for
the M-Value Register and select the CPU output frequency by
changing the value of the N-Value Register.
RESET WATCHDOG TIMER
Set WD(0:3) Bits = 0
INITIALIZE WATCHDOG TIMER
Set Frequency Revert Bit
Set WD(0:3) = (# of Sec ) x 2
SET SOFTWARE FSEL
Set SW Freq_Sel = 1
Set FS(0:4)
Wait for 6msec For
Clock Output to Ramp to
Target Frequency
Hang
Y
WATCHDOG TIMEOUT
N
CLEAR WD
Set WD(0:3) Bits = 0
Exit
Reset
Frequency Revert Bit =
0
Set Frequency to
FS_HW_Latched
Frequency Revert Bit =
1
Set Frequency to FS_SW
Set SRESET# = 0 for 6 msec
SET DIAL-A-FREQUENCY
Load M and N Registers
Set Pro_Freq_EN = 1
Figure 1. Watchdog Flowchart
Frequency Ranges
66 – 127
128 – 203
Gear Constants
47.99750
63.99667
Fixed Value for M-Value Register
48
40
Range of N-Value Register for Different
CPU Frequency
66 – 127
80 – 127
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| CY28378OC | FTG for Pentium 4 and Intel 845 Series Chipset |
| CY28378OCT | FTG for Pentium 4 and Intel 845 Series Chipset |
| CY28400 | 100-MHz Differential Buffer for PCI Express and SATA |
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| CY28378OC | 制造商:SPECTRALINEAR 制造商全稱:SPECTRALINEAR 功能描述:FTG for Pentium 4㈢ and Intel㈢ 845 Series Chipset |
| CY28378OCT | 制造商:SPECTRALINEAR 制造商全稱:SPECTRALINEAR 功能描述:FTG for Pentium 4㈢ and Intel㈢ 845 Series Chipset |
| CY28378OXC | 功能描述:時(shí)鐘發(fā)生器及支持產(chǎn)品 Sys Clk Pentium 4 & Intel Brookdale 845 RoHS:否 制造商:Silicon Labs 類型:Clock Generators 最大輸入頻率:14.318 MHz 最大輸出頻率:166 MHz 輸出端數(shù)量:16 占空比 - 最大:55 % 工作電源電壓:3.3 V 工作電源電流:1 mA 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:QFN-56 |
| CY28378OXCT | 功能描述:時(shí)鐘發(fā)生器及支持產(chǎn)品 Sys Clk Pentium 4 & Intel Brookdale 845 RoHS:否 制造商:Silicon Labs 類型:Clock Generators 最大輸入頻率:14.318 MHz 最大輸出頻率:166 MHz 輸出端數(shù)量:16 占空比 - 最大:55 % 工作電源電壓:3.3 V 工作電源電流:1 mA 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:QFN-56 |
| CY28381 | 制造商:CYPRESS 制造商全稱:Cypress Semiconductor 功能描述:High-Performance SiS645DX/648DX/650/651 Intel Pentium 4 Clock Synthesizer |
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