參數(shù)資料
型號: M41ST85WMH6TR
廠商: STMICROELECTRONICS
元件分類: 時(shí)鐘/數(shù)據(jù)恢復(fù)及定時(shí)提取
英文描述: 1 TIMER(S), REAL TIME CLOCK, PDSO28
封裝: 0.300 INCH, SNAPHAT, PLASTIC, SOH-28
文件頁數(shù): 17/41頁
文件大?。?/td> 376K
代理商: M41ST85WMH6TR
Clock operation
M41ST85W
Figure 16.
Backup mode alarm waveform
3.5
Watchdog timer
The watchdog timer can be used to detect an out-of-control microprocessor. The user
programs the watchdog timer by setting the desired amount of time-out into the watchdog
register, address 09h. Bits BMB4-BMB0 store a binary multiplier and the two lower order bits
RB1-RB0 select the resolution, where 00 = 1/16 second, 01 = 1/4 second, 10 = 1 second,
and 11 = 4 seconds. The amount of time-out is then determined to be the multiplication of
the five-bit multiplier value with the resolution. (For example: writing 00001110 in the
watchdog register = 3*1 or 3 seconds).
Note:
The accuracy of the timer is within ± the selected resolution.
If the processor does not reset the timer within the specified period, the M41ST85W sets the
WDF (watchdog flag) and generates a watchdog interrupt or a microprocessor reset.
The most significant bit of the watchdog register is the watchdog steering bit (WDS). When
set to a '0,' the watchdog will activate the IRQ/FT/OUT pin when timed-out. When WDS is
set to a '1,' the watchdog will output a negative pulse on the RST pin for trec. The watchdog
register, FT, AFE, ABE and SQWE bits will reset to a '0' at the end of a watchdog time-out
when the WDS bit is set to a '1.'
The watchdog timer can be reset by two methods: 1) a transition (high-to-low or low-to-high)
can be applied to the watchdog input pin (WDI) or 2) the microprocessor can perform a
WRITE of the watchdog register. The time-out period then starts over.
Note:
The WDI pin should be tied to VSS if not used.
In order to perform a software reset of the watchdog timer, the original time-out period can
be written into the watchdog register, effectively restarting the count-down cycle.
Should the watchdog timer time-out, and the WDS bit is programmed to output an interrupt,
a value of 00h needs to be written to the watchdog register in order to clear the IRQ/FT/OUT
AI03920
VCC
IRQ/FT/OUT
VPFD
ABE, AFE Bits in Interrupt Register
AF bit in Flags Register
HIGH-Z
VSO
HIGH-Z
trec
相關(guān)PDF資料
PDF描述
M41ST85WMH6E 1 TIMER(S), REAL TIME CLOCK, PDSO28
M41ST87WMX6 1 TIMER(S), REAL TIME CLOCK, PDSO28
M41ST87YMX6 1 TIMER(S), REAL TIME CLOCK, PDSO28
M41ST87YMX6TR 1 TIMER(S), REAL TIME CLOCK, PDSO28
M41ST87WMX6TR 1 TIMER(S), REAL TIME CLOCK, PDSO28
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
M41ST85WMSX6 制造商: 功能描述: 制造商:undefined 功能描述:
M41ST85WMX 制造商:STMICROELECTRONICS 制造商全稱:STMicroelectronics 功能描述:5.0 OR 3.0V, 512 bit 64 x 8 SERIAL RTC and NVRAM SUPERVISOR
M41ST85WMX6 功能描述:實(shí)時(shí)時(shí)鐘 Serial 512 (64x8) RoHS:否 制造商:Microchip Technology 功能:Clock, Calendar. Alarm RTC 總線接口:I2C 日期格式:DW:DM:M:Y 時(shí)間格式:HH:MM:SS RTC 存儲容量:64 B 電源電壓-最大:5.5 V 電源電壓-最小:1.8 V 最大工作溫度:+ 85 C 最小工作溫度: 安裝風(fēng)格:Through Hole 封裝 / 箱體:PDIP-8 封裝:Tube
M41ST85WMX6E 制造商:STMicroelectronics 功能描述:
M41ST85WMX6E2 制造商:STME 功能描述: 制造商:STMicroelectronics 功能描述: