Clocked from separate On-chip Oscil" />
參數(shù)資料
型號: SC16C654BIA68,529
廠商: NXP Semiconductors
文件頁數(shù): 50/58頁
文件大?。?/td> 0K
描述: IC QUAD UART 64BYTE 68PLCC
標準包裝: 18
特點: 故障啟動位檢測
通道數(shù): 4,QUART
FIFO's: 64 字節(jié)
電源電壓: 2.5V,3.3V,5V
帶自動流量控制功能:
帶IrDA 編碼器/解碼器:
帶故障啟動位檢測功能:
帶調制解調器控制功能:
帶CMOS:
安裝類型: 表面貼裝
封裝/外殼: 68-LCC(J 形引線)
供應商設備封裝: 68-PLCC
包裝: 管件
其它名稱: 935274935529
SC16C654BIA68-S
SC16C654BIA68-S-ND
54
7674F–AVR–09/09
ATmega164P/324P/644P
9.2
Watchdog Timer
9.2.1
Features
Clocked from separate On-chip Oscillator
3 Operating modes
–Interrupt
– System Reset
– Interrupt and System Reset
Selectable Time-out period from 16ms to 8s
Possible Hardware fuse Watchdog always on (WDTON) for fail-safe mode
9.2.2
Overview
ATmega164P/324P/644P has an Enhanced Watchdog Timer (WDT). The WDT is a timer count-
ing cycles of a separate on-chip 128 kHz oscillator. The WDT gives an interrupt or a system
reset when the counter reaches a given time-out value. In normal operation mode, it is required
that the system uses the WDR - Watchdog Timer Reset - instruction to restart the counter before
the time-out value is reached. If the system doesn't restart the counter, an interrupt or system
reset will be issued.
Figure 9-5.
Watchdog Timer
In Interrupt mode, the WDT gives an interrupt when the timer expires. This interrupt can be used
to wake the device from sleep-modes, and also as a general system timer. One example is to
limit the maximum time allowed for certain operations, giving an interrupt when the operation
has run longer than expected. In System Reset mode, the WDT gives a reset when the timer
expires. This is typically used to prevent system hang-up in case of runaway code. The third
mode, Interrupt and System Reset mode, combines the other two modes by first giving an inter-
rupt and then switch to System Reset mode. This mode will for instance allow a safe shutdown
by saving critical parameters before a system reset.
The Watchdog always on (WDTON) fuse, if programmed, will force the Watchdog Timer to Sys-
tem Reset mode. With the fuse programmed the System Reset mode bit (WDE) and Interrupt
mode bit (WDIE) are locked to 1 and 0 respectively. To further ensure program security, altera-
tions to the Watchdog set-up must follow timed sequences. The sequence for clearing WDE and
changing time-out configuration is as follows:
128kHz
OSCILLATOR
OSC/2K
OSC/4K
OSC/8K
OSC/16K
OSC/32K
OSC/64K
OSC/128K
OSC/256K
OSC/512K
OSC/1024K
WDP0
WDP1
WDP2
WDP3
WATCHDOG
RESET
WDE
WDIF
WDIE
MCU RESET
INTERRUPT
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SC16C654BIA68-S 功能描述:UART 接口集成電路 16CB 2.5V-5V 4CH UART 64B FIFO RoHS:否 制造商:Texas Instruments 通道數(shù)量:2 數(shù)據(jù)速率:3 Mbps 電源電壓-最大:3.6 V 電源電壓-最小:2.7 V 電源電流:20 mA 最大工作溫度:+ 85 C 最小工作溫度:- 40 C 封裝 / 箱體:LQFP-48 封裝:Reel
SC16C654BIA68-T 功能描述:UART 接口集成電路 16CB 2.5V-5V 4CH UART 64B FIFO RoHS:否 制造商:Texas Instruments 通道數(shù)量:2 數(shù)據(jù)速率:3 Mbps 電源電壓-最大:3.6 V 電源電壓-最小:2.7 V 電源電流:20 mA 最大工作溫度:+ 85 C 最小工作溫度:- 40 C 封裝 / 箱體:LQFP-48 封裝:Reel
SC16C654BIB64 功能描述:UART 接口集成電路 16CB 2.5V-5V 4CH UART 64B FIFO RoHS:否 制造商:Texas Instruments 通道數(shù)量:2 數(shù)據(jù)速率:3 Mbps 電源電壓-最大:3.6 V 電源電壓-最小:2.7 V 電源電流:20 mA 最大工作溫度:+ 85 C 最小工作溫度:- 40 C 封裝 / 箱體:LQFP-48 封裝:Reel
SC16C654BIB64,128 功能描述:UART 接口集成電路 16CB 2.5V-5V 4CH RoHS:否 制造商:Texas Instruments 通道數(shù)量:2 數(shù)據(jù)速率:3 Mbps 電源電壓-最大:3.6 V 電源電壓-最小:2.7 V 電源電流:20 mA 最大工作溫度:+ 85 C 最小工作溫度:- 40 C 封裝 / 箱體:LQFP-48 封裝:Reel
SC16C654BIB64,151 功能描述:UART 接口集成電路 16CB 2.5V-5V 4CH RoHS:否 制造商:Texas Instruments 通道數(shù)量:2 數(shù)據(jù)速率:3 Mbps 電源電壓-最大:3.6 V 電源電壓-最小:2.7 V 電源電流:20 mA 最大工作溫度:+ 85 C 最小工作溫度:- 40 C 封裝 / 箱體:LQFP-48 封裝:Reel