參數(shù)資料
型號: ATWEBDVK-02WC
廠商: Atmel
文件頁數(shù): 121/137頁
文件大?。?/td> 0K
描述: KIT DEV TCP/IP AT89C51RD2 WEBCAM
標(biāo)準(zhǔn)包裝: 1
系列: @Web
主要目的: *
嵌入式: *
已用 IC / 零件: AT89C51RD2
主要屬性: *
次要屬性: *
已供物品: 板,帶網(wǎng)絡(luò) Webcam 模塊和軟件
產(chǎn)品目錄頁面: 617 (CN2011-ZH PDF)
84
4235K–8051–05/08
AT89C51RD2/ED2
19. Hardware Watchdog Timer
The WDT is intended as a recovery method in situations where the CPU may be subjected to
software upset. The WDT consists of a 14-bit counter and the Watchdog Timer ReSeT
(WDTRST) SFR. The WDT is by default disabled from exiting reset. To enable the WDT, user
must write 01EH and 0E1H in sequence to the WDTRST, SFR location 0A6H. When WDT is
enabled, it will increment every machine cycle while the oscillator is running and there is no way
to disable the WDT except through reset (either hardware reset or WDT overflow reset). When
WDT overflows, it will drive an output RESET HIGH pulse at the RST-pin.
19.1
Using the WDT
To enable the WDT, user must write 01EH and 0E1H in sequence to the WDTRST, SFR loca-
tion 0A6H. When WDT is enabled, the user needs to service it by writing to 01EH and 0E1H to
WDTRST to avoid WDT overflow. The 14-bit counter overflows when it reaches 16383 (3FFFH)
and this will reset the device. When WDT is enabled, it will increment every machine cycle while
the oscillator is running. This means the user must reset the WDT at least every 16383 machine
cycle. To reset the WDT the user must write 01EH and 0E1H to WDTRST. WDTRST is a write
only register. The WDT counter cannot be read or written. When WDT overflows, it will generate
an output RESET pulse at the RST-pin. The RESET pulse duration is 96 x TCLK PERIPH, where
TCLK PERIPH= 1/FCLK PERIPH. To make the best use of the WDT, it should be serviced in those sec-
tions of code that will periodically be executed within the time required to prevent a WDT reset.
To have a more powerful WDT, a 27 counter has been added to extend the Time-out capability,
ranking from 16 ms to 2s @ FOSCA = 12 MHz. To manage this feature, refer to WDTPRG register
description, Table 19-1. The WDTPRG register should be configured before the WDT activation
sequence, and can not be modified until next reset.
Table 19-1.
WDTRST Register
WDTRST - Watchdog Reset Register (0A6h)
Reset Value = XXXX XXXXb
Write only, this SFR is used to reset/enable the WDT by writing 01EH then 0E1H in sequence.
7
6
5
4
3
2
1
0
-
相關(guān)PDF資料
PDF描述
VRE210MA IC VREF SERIES PREC 10V 20-CLCC
VRE204M IC VREF SERIES PREC 4.5V 20-CLCC
ATWEBDVK-02VOIP KIT DEV TCP/IP AT89C51RD2 VOIP
A3DDB-1018G IDC CABLE- AKR10B/AE10G/AKR10B
V24C12E150BL3 CONVERTER MOD DC/DC 12V 150W
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
ATWEBEVK-01 功能描述:KIT EVAL TCP/IP AT89C51AC2 RoHS:否 類別:編程器,開發(fā)系統(tǒng) >> 評估演示板和套件 系列:@Web 產(chǎn)品培訓(xùn)模塊:Obsolescence Mitigation Program 標(biāo)準(zhǔn)包裝:1 系列:- 主要目的:電源管理,電池充電器 嵌入式:否 已用 IC / 零件:MAX8903A 主要屬性:1 芯鋰離子電池 次要屬性:狀態(tài) LED 已供物品:板
ATWEBEVK-02 功能描述:KIT SOFTWARE EVAL FOR T89C51CC01 制造商:microchip technology 系列:- 零件狀態(tài):停產(chǎn) 主要用途:接口,以太網(wǎng) 嵌入式:- 使用的 IC/零件:- 主要屬性:- 輔助屬性:- 所含物品:板 標(biāo)準(zhǔn)包裝:1
ATWEBEVK-05 功能描述:KIT EVAL MODULE RS232 TO TCP/IP RoHS:否 類別:編程器,開發(fā)系統(tǒng) >> 評估演示板和套件 系列:@Web 產(chǎn)品培訓(xùn)模塊:Obsolescence Mitigation Program 標(biāo)準(zhǔn)包裝:1 系列:- 主要目的:電源管理,電池充電器 嵌入式:否 已用 IC / 零件:MAX8903A 主要屬性:1 芯鋰離子電池 次要屬性:狀態(tài) LED 已供物品:板
ATWEBEVK-06 功能描述:BOARD EVAL FOR CAN-ETHERNET MOD RoHS:否 類別:編程器,開發(fā)系統(tǒng) >> 評估演示板和套件 系列:@Web 產(chǎn)品培訓(xùn)模塊:Obsolescence Mitigation Program 標(biāo)準(zhǔn)包裝:1 系列:- 主要目的:電源管理,電池充電器 嵌入式:否 已用 IC / 零件:MAX8903A 主要屬性:1 芯鋰離子電池 次要屬性:狀態(tài) LED 已供物品:板
ATWEBSEG-32 功能描述:MODULE RS232 TO TCP/IP RoHS:否 類別:編程器,開發(fā)系統(tǒng) >> 過時/停產(chǎn)零件編號 系列:- 標(biāo)準(zhǔn)包裝:1 系列:- 類型:MCU 適用于相關(guān)產(chǎn)品:Freescale MC68HC908LJ/LK(80-QFP ZIF 插口) 所含物品:面板、纜線、軟件、數(shù)據(jù)表和用戶手冊 其它名稱:520-1035