參數(shù)資料
型號(hào): MQ80C52EXXX-20P883R
廠商: ATMEL CORP
元件分類: 微控制器/微處理器
英文描述: 8-BIT, MROM, 20 MHz, MICROCONTROLLER, CQFP44
封裝: CERAMIC, QFP-44
文件頁數(shù): 14/91頁
文件大?。?/td> 19688K
代理商: MQ80C52EXXX-20P883R
26
7707F–AVR–11/10
AT90USB82/162
6.1.4
USB Clock – clk
USB
The USB is provided with a dedicated clock domain. This clock is generated with an on-chip PLL
running at 48MHz. The PLL always multiply its input frequency by 6. Thus the PLL clock register
should be programmed by software to generate a 8MHz clock on the PLL input.
6.2
Clock Switch
In the AT90USB82/162 product, the Clock Multiplexer and the System Clock Prescaler can be
modified by software.
6.2.1
Exemple of use
The modification can occur when the device enters in USB Suspend mode. It then switches from
External Clock to Calibrated RC Oscillator in order to reduce consumption. In such a configura-
tion, the External Clock is disabled.
The firmware can use the watchdog timer to be woken-up from power-down in order to check if
there is an event on the application.
If an event occurs on the application or if the USB controller signals a non-idle state on the USB
line (Resume for example), the firmware switches the Clock Multiplexer from the Calibrated RC
Oscillator to the External Clock.
Figure 6-2.
Example of clock switching with wake-up from USB Host
USB
CPU Clock
External
Oscillator
RC oscillator
Ext
RC
Ext
non-Idle
Idle
(Suspend)
non-Idle
3m
s
resume
1
1 Resume from Host
watchdog wake-up
from power-down
相關(guān)PDF資料
PDF描述
MQ80C32E-25SCR 8-BIT, 25 MHz, MICROCONTROLLER, CQFP44
MR80C52EXXX-36/883:RD 8-BIT, MROM, 36 MHz, MICROCONTROLLER, CQCC44
MR80C52TXXX-20SHXXX:R 8-BIT, MROM, 20 MHz, MICROCONTROLLER, CQCC44
MR80C52XXX-36/883:RD 8-BIT, MROM, 36 MHz, MICROCONTROLLER, CQCC44
MD83C154TXXX-20P883 8-BIT, MROM, 20 MHz, MICROCONTROLLER, CDIP40
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
MQ82370-20 制造商:Rochester Electronics LLC 功能描述:- Bulk
MQ8238020 制造商:Intel 功能描述:CONTROLLER: OTHER
MQ82380-20 制造商:Rochester Electronics LLC 功能描述:- Bulk
MQ82380-20/R 制造商:Rochester Electronics LLC 功能描述:
MQ82592 制造商:Rochester Electronics LLC 功能描述:- Bulk