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參數(shù)資料
型號: DS1670S
廠商: Maxim Integrated Products
文件頁數(shù): 14/16頁
文件大?。?/td> 0K
描述: IC CTRLR SYSTEM PORTABLE 20-SOIC
產(chǎn)品培訓模塊: Lead (SnPb) Finish for COTS
Obsolescence Mitigation Program
標準包裝: 37
類型: 便攜系統(tǒng)控制器
特點: 警報器,閏年,監(jiān)視計時器
時間格式: HH:MM:SS(12/24 小時)
數(shù)據(jù)格式: YY-MM-DD-dd
接口: 3 線串口
電源電壓: 2.97 V ~ 3.63 V
電壓 - 電源,電池: 2.5 V ~ 3.7 V
工作溫度: 0°C ~ 70°C
安裝類型: 表面貼裝
封裝/外殼: 20-SOIC(0.295",7.50mm 寬)
供應商設備封裝: 20-SOIC W
包裝: 管件
DS1670
7 of 16
The DS1670 nonvolatilizes the external SRAM(s) by write protecting the SRAM(s) and by providing a
back-up power supply in the absence of VCC. When VCC falls below 2.88V (typical), access to the
external SRAM(s) are prohibited by forcing CEOL and CEOH high regardless of the level of CEI , BLE ,
and BHE . Also at this point, the SRAM power supply (VCCO) is switched from VCC to VBAT. Upon power-
up, access is prohibited until the end of tRPU.
EXTERNAL SRAM CHIP ENABLE Table 3
CEI
BHE
BLE
CEOL
CEOH
FUNCTION
0
Word Transfer
0
1
0
Byte Transfer in upper half of data bus (D15-D8)
0
1
0
1
Byte Transfer in lower half of data bus (D7-D0)
0
1
External SRAMs disabled
1
X
1
External SRAMs disabled
EXTERNAL SRAM INTERFACE (WORD-WIDE) TO THE DS1670 Figure 4
MICROPROCESSOR MONITOR
The DS1670 monitors three vital conditions for a microprocessor: power supply, software execution, and
external override.
First, a precision temperature-compensated reference and comparator circuit monitors the status of VCC.
When an out-of-tolerance condition occurs, an internal power-fail signal is generated which forces the
RST
pin to the active state, thus warning a processor-based system of impending power failure. The
power-fail trip point is 2.88V (typical). When VCC returns to an in-tolerance condition upon power-up,
the reset signal is kept in the active state for 250ms (typical) to allow the power supply and
microprocessor to stabilize. Note, however, that if the EOSC bit is set to a logic 1 (to disable the oscillator
during battery-backup mode), the reset signal will be kept in an active state for 250ms plus the startup
time of the oscillator.
The second monitoring function is pushbutton reset control. The DS1670 provides for a pushbutton
switch to be connected to the RST output pin. When the DS1670 is not in a reset cycle, it continuously
monitors the RST signal for a low-going edge. If an edge is detected, the DS1670 will debounce the
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