M41T81 串行访问实时时钟带闹钟
The M41T81 is a low power serial RTC with a built-in 32.768 kHz oscillator (external crystal controlled). Eight bytes of the SRAM (see Table 2: Clock register map on page 14) are used for the clock/calendar function and are configured in binary coded decimal (BCD) format. An additional 12 bytes of SRAM provide status/control of Alarm, Watchdog and Square Wavefunctions. Addresses and data are transferred serially via a two line, bidirectional I2C interface. The built-in address register is incremented automatically after each WRITE or READ data byte.
The M41T81 has a built-in power sense circuit which detects power failures and automatically switches to the battery supply when a power failure occurs. The energy needed to sustain the SRAM and clock operations can be supplied by a small lithium button supply when a power failure occurs. Functions available to the user include a non-volatile, time-of-day clock/calendar, alarm interrupts, watchdog timer and programmable square wave output. The eight clock address locations contain the century, year, month, date, day, hour, minute, second and tenths/hundredths of a second in 24-hour BCD format. Corrections for 28, 29 (leap year -valid until year 2100), 30 and 31 day months are made automatically.
M41T81 订购型号:
| Ordering Model | Package | RoHS Compliance Grade | Marketing Status | Memory Organization | Supply Voltage(Vcc) | Supply Voltage(Vcc) | General Description | Programmable Alarms | Watchdog Timer | Square Wave Output(SQW) | Operating Range | Battery Switchover(VSO) | Battery Low Detect(BL) | Packing Type |
| min | max | |||||||||||||
| V | V | |||||||||||||
| M41T81M6E | SO8 | Ecopack1 | Active | 160b (20 x 8) | 2 | 5.5 | See M41T81S | Yes | Yes | Yes | Industrial | Yes | Yes | Tube |
| M41T81M6F | SO8 | Ecopack1 | Active | 160b (20 x 8) | 2 | 5.5 | See M41T81S | Yes | Yes | Yes | Industrial | Yes | Yes | Tape And Reel |
M41T81 产品特性:
- For new designs use M41T81S
- Counters for tenths/hundredths of seconds,seconds, minutes, hours, day, date, month,year, and century
- 32 KHz crystal oscillator integrating load capacitance (12.5 pF) providing exceptional oscillator stability and high crystal series resistance operation
- Serial interface supports I2C bus (400 kHz protocol)
- Ultra-low battery supply current of 0.6 μA (typ at 3 V)
- 2.0 to 5.5 V clock operating voltage
- Automatic switch-over and deselect circuitry (for 3V application select M41T81S datasheet)
- Power-down time stamp (HT bit) allowing determination of time elapsed in battery backup
- Programmable alarm and interrupt function (valid even during battery backup mode)
- Accurate programmable watchdog timer (from 62.5 ms to 128 s)
- Software clock calibration to compensate crystal deviation due to temperature
- Operating temperature of –40 to 85°C
- ECOPACK? package available
M41T81 技术支持与电子电路设计开发资源下载
- M41T81 数据手册DataSheet下载.PDF
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