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参数资料
| 型号： | M48T37 |
| 厂商： | 意法半导体 |
| 英文描述： | 3.3V-5V 256 Kbit 32Kb x8 TIMEKEEPER SRAM |
| 中文描述： | 3.3 - 5V的256千位的32KB的SRAM x8计时器 |
| 文件页数： | 14/20页 |
| 文件大小： | 128K |
| 代理商： | M48T37 |
M48T37Y, M48T37V
14/20
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 eight bit Watchdog Register, ad-
dress 7FF7h. The five bits (BMB4-BMB0) store a
binary multiplier andthe two lower order bits (RB1-
RB0) select the resolution, where 00 = 1/16 sec-
ond, 01 = 1/4second, 10 = 1 second, and 11 = 4
seconds. The amount of time-out is then deter-
mined to be the multiplication of the five bit multi-
plier value with the resolution. (For example:
writing 00001110 in the Watchdog Register = 3x1
or 3 seconds).
Note
: Accuracy of timer is within
±
the selected
resolution.
If theprocessor does not reset the timer within the
specified period, the M48T37Y/37V sets the
Watchdog Flag (WDF)and generates a watchdog
interrupt or a microprocessor reset. WDF is reset
by reading the Flags Register (Address 1FF0h).
The most significant bit of the Watchdog Register
is the Watchdog Steering Bit.When setto a ‘0’, the
watchdog will activatethe IRQ/FT pin when timed-
out. When WDS is set to a ‘1’, the watchdog will
output a negative pulse on the RST pin for a dura-
tion of 40ms to 200ms. The Watchdog registerand
the FT bit will reset to a ’0’ at the end of a Watch-
dog time-out when the WDS bit is set to a ‘1’.
The watchdog timer resets when themicroproces-
sor performs a re-write of the Watchdog Register
or an edge transition, (low to high / high to low) on
the WDI pin occurs. The time-out period then
starts over.
The watchdog timer is disabled by writing a value
of 00000000to the eight bits in theWatchdog Reg-
ister. Should the watchdog timertime out, a value
of 00h needs to be written to theWatchdog Regis-
ter in order to clear the IRQ/FT pin.
The watchdog function is automatically disabled
upon power-down and the Watchdog Register is
cleared. If the watchdog function is set to output to
the IRQ/FT pin and the frequency test function is
activated, the watchdog or alarm function prevails
and the frequency testfunction is denied. The WDI
pin should be connected to V
SS
if not used.
Figure 12. Back-up Mode Alarm Waveforms
AI03254B
VCC
VPFD(max)
VPFD(min)
IRQ/FT
tREC
ABE, AFE bit in Interrupt Register
AF bit in Flags Register
HIGH-Z
VSO
HIGH-Z
Table 12. Alarm Repeat Mode
RPT4
RPT3
RPT2
RPT1
Alarm Activated
1
1
1
1
Once per Second
1
1
1
0
Once per Minute
1
1
0
0
Once per Hour
1
0
0
0
Once per Day
0
0
0
0
Once per Month
相关PDF资料 |
PDF描述 |
|---|---|
| M48T37YSH | Hook-Up Wire; Conductor Size AWG:24; No. Strands x Strand Size:Solid; Jacket Color:Orange; Approval Bodies:UL, CSA; Approval Categories:UL AWM Style 1061; CSA AWM; Conductor Material:Copper; Jacket Material:Polyvinylchloride (PVC) RoHS Compliant: Yes |
| M48T37V-10MH6TR | DIODE ZENER DUAL ISOLATED 200mW 3.3Vz 5mA-Izt 0.0606 5uA-Ir 1 SOT-363 3K/REEL |
| M48T37V-70MH1TR | DIODE ZENER SINGLE 300mW 3.6Vz 5mA-Izt 0.0556 5uA-Ir 1 SOT-23 3K/REEL |
| M48T37V-70MH6 | DIODE ZENER DUAL ISOLATED 200mW 3.6Vz 5mA-Izt 0.0556 5uA-Ir 1 SOT-363 3K/REEL |
| M48T37V-70MH6TR | DIODE ZENER SINGLE 150mW 3.6Vz 5mA-Izt 0.0556 5uA-Ir 1 SOT-523 3K/REEL |
相关代理商/技术参数 |
参数描述 |
|---|---|
| M48T37V | 制造商:STMICROELECTRONICS 制造商全称:STMicroelectronics 功能描述:3.3V-5V 256 Kbit 32Kb x8 TIMEKEEPER SRAM |
| M48T37V-10MH1 | 制造商:STMICROELECTRONICS 制造商全称:STMicroelectronics 功能描述:5.0 or 3.3 V, 256 Kbit (32 Kbit x 8) TIMEKEEPER? SRAM |
| M48T37V-10MH1E | 功能描述:实时时钟 256K (32Kx8) 100ns RoHS:否 制造商:Microchip Technology 功能:Clock, Calendar. Alarm RTC 总线接口:I2C 日期格式:DW:DM:M:Y 时间格式:HH:MM:SS RTC 存储容量:64 B 电源电压-最大:5.5 V 电源电压-最小:1.8 V 最大工作温度:+ 85 C 最小工作温度: 安装风格:Through Hole 封装 / 箱体:PDIP-8 封装:Tube |
| M48T37V-10MH1F | 功能描述:实时时钟 256K (32Kx8) 100ns RoHS:否 制造商:Microchip Technology 功能:Clock, Calendar. Alarm RTC 总线接口:I2C 日期格式:DW:DM:M:Y 时间格式:HH:MM:SS RTC 存储容量:64 B 电源电压-最大:5.5 V 电源电压-最小:1.8 V 最大工作温度:+ 85 C 最小工作温度: 安装风格:Through Hole 封装 / 箱体:PDIP-8 封装:Tube |
| M48T37V-10MH1TR | 制造商:STMICROELECTRONICS 制造商全称:STMicroelectronics 功能描述:3.3V-5V 256 Kbit 32Kb x8 TIMEKEEPER SRAM |
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