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参数资料
| 型号： | M48T212V-85MH1E |
| 厂商： | STMICROELECTRONICS |
| 元件分类： | 时钟/数据恢复及定时提取 |
| 英文描述： | REAL TIME CLOCK, PDSO44 |
| 封装： | 0.330 INCH, ROHS COMPLIANT, PLASTIC, SOH-44 |
| 文件页数： | 35/35页 |
| 文件大小： | 348K |
| 代理商： | M48T212V-85MH1E |
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M48T212V
Operation
2
Operation
Automatic backup and write protection for an external SRAM is provided through VOUT,
E1CON and E2CON pins. (Users are urged to ensure that voltage specifications, for both the
SUPERVISOR chip and external SRAM chosen, are similar). The SNAPHAT containing
the lithium energy source used to permanently power the real-time clock is also used to
retain RAM data in the absence of VCC power through the VOUT pin.
The chip enable outputs to RAM (E1CON and E2CON) are controlled during power transients
to prevent data corruption. The date is automatically adjusted for months with less than 31
days and corrects for leap years (valid until 2100). The internal watchdog timer provides
programmable alarm windows.
The nine clock bytes (Fh-9h and 1h) are not the actual clock counters, they are memory
locations consisting of BiPORT READ/WRITE memory cells within the static RAM array.
Clock circuitry updates the clock bytes with current information once per second. The
information can be accessed by the user in the same manner as any other location in the
static memory array.
Byte 8h is the clock control register. This byte controls user access to the clock information
and also stores the clock calibration setting. Byte 7h contains the watchdog timer setting.
The watchdog timer can generate either a reset or an interrupt, depending on the state of
the Watchdog Steering Bit (WDS). Bytes 6h-2h include bits that, when programmed, provide
for clock alarm functionality.
Alarms are activated when the register content matches the month, date, hours, minutes,
and seconds of the clock registers. Byte 1h contains century information. Byte 0h contains
additional flag information pertaining to the watchdog timer, alarm and battery status.
The M48T212V also has its own Power-Fail Detect circuit. This control circuitry constantly
monitors the supply voltage for an out of tolerance condition. When VCC is out of tolerance,
the circuit write protects the TIMEKEEPER register data and external SRAM, providing
data security in the midst of unpredictable system operation. As VCC falls below VSO, the
control circuitry automatically switches to the battery, maintaining data and clock operation
until valid power is restored.
2.1
Address decoding
The M48T212YV accommodates 4 address lines (A3-A0) which allow access to the sixteen
bytes of the TIMEKEEPER clock registers. All TIMEKEEPER registers reside in the
SUPERVISOR chip itself. All TIMEKEEPER registers are accessed by enabling E (Chip
Enable).
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PDF描述 |
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相关代理商/技术参数 |
参数描述 |
|---|---|
| M48T212V-85MH1F | 功能描述:监控电路 SRAM TK 16X8 85ns RoHS:否 制造商:STMicroelectronics 监测电压数: 监测电压: 欠电压阈值: 过电压阈值: 输出类型:Active Low, Open Drain 人工复位:Resettable 监视器:No Watchdog 电池备用开关:No Backup 上电复位延迟（典型值）:10 s 电源电压-最大:5.5 V 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:UDFN-6 封装:Reel |
| M48T212V-85MH1TR | 制造商:STMICROELECTRONICS 制造商全称:STMicroelectronics 功能描述:5V/3.3V TIMEKEEPER[ CONTROLLER |
| M48T212V-85MH6 | 制造商:STMICROELECTRONICS 制造商全称:STMicroelectronics 功能描述:5V/3.3V TIMEKEEPER[ CONTROLLER |
| M48T212V-85MH6E | 制造商:STMICROELECTRONICS 制造商全称:STMicroelectronics 功能描述:5V/3.3V TIMEKEEPER CONTROLLER Supervisor |
| M48T212V-85MH6F | 制造商:STMICROELECTRONICS 制造商全称:STMicroelectronics 功能描述:5V/3.3V TIMEKEEPER CONTROLLER Supervisor |
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