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| 型號： | CY28331 |
| 英文描述： | Clocks and Buffers |
| 中文描述： | 時鐘和緩沖器 |
| 文件頁數(shù)： | 12/17頁 |
| 文件大?。?/td> | 240K |
| 代理商： | CY28331 |
CY28312B-2
Document #: 38-07596 Rev. **
Page 12 of 17
How to Program 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 + 3)/(M + 3).
“N” and “M” are the values programmed in Programmable
Frequency Select N-Value Register and M-Value Register,
respectively.
“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 4
. The ratio of (N + 3) and (M + 3) needs to be
greater than “1” [(N + 3)/(M + 3) > 1].
Table 6
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.
WD_TIMER[4:0]
These bits store the time-out value of the Watchdog timer. The scale of the timer is determine by the
prescaler.
The timer can support a value of 150 ms to 4.8 sec when the pre-scaler is set to 150 ms. If the pre-scaler
is set to 2.5 sec, it can support a value from 2.5 sec to 80 sec.
When the Watchdog timer reaches “0”, it will set the WD_TO_STATUS bit.
0 = 150 ms
1 = 2.5 sec
This bit will enable the generation of a Reset pulse when a Watchdog timer time-out occurs.
0 = Disabled
1 = Enabled
This bit will enable the generation of a Reset pulse after a frequency change occurs.
0 = Disabled
1 = Enabled
WD_PRE_SCALER
RST_EN_WD
RST_EN_FC
Table 5. Register Summary
(continued)
Name
Description
Table 6. Examples of N and M Value for Different CPU Frequency Range
Frequency Ranges
50 MHz–129 MHz
130 MHz–248 MHz
Gear Constants
48.00741
48.00741
Fixed Value for
M-Value Register
93
48
Range of N-Value Register
for Different CPU Frequency
97–255
127–245
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| CY28331-2 | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Clocks and Buffers |
| CY28331OC | 制造商:Rochester Electronics LLC 功能描述:- Bulk |
| CY28331OC-2 | 制造商:Rochester Electronics LLC 功能描述:- Bulk |
| CY28331OCT | 制造商:SPECTRALINEAR 制造商全稱:SPECTRALINEAR 功能描述:Clock Generator for AMD⑩ Hammer |
| CY28331OXC | 功能描述:IC CLOCK GEN AMD 48-SSOP RoHS:是 類別:集成電路 (IC) >> 時鐘/計時 - 時鐘發(fā)生器，PLL，頻率合成器 系列:- 產(chǎn)品變化通告:Product Discontinuation 04/May/2011 標準包裝:96 系列:- 類型:時鐘倍頻器，零延遲緩沖器 PLL:帶旁路 輸入:LVTTL 輸出:LVTTL 電路數(shù):1 比率 - 輸入:輸出:1:8 差分 - 輸入:輸出:無/無 頻率 - 最大:133.3MHz 除法器/乘法器:是/無 電源電壓:3 V ~ 3.6 V 工作溫度:0°C ~ 70°C 安裝類型:表面貼裝 封裝/外殼:16-TSSOP（0.173"，4.40mm 寬） 供應(yīng)商設(shè)備封裝:16-TSSOP 包裝:管件 其它名稱:23S08-5HPGG |
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