M48T201Y-70MH1E STMicroelectronics, M48T201Y-70MH1E Datasheet - Page 20

• Manufacturer Part Number: M48T201Y-70MH1E
• Description: IC SUPERVISOR TIMEKPR 5V 44-SOH
• Manufacturer: STMicroelectronics
• Series: Timekeeper®r
• Type: Clock/Calendar/NVSRAMr

Specifications of M48T201Y-70MH1E

• Memory Size: External
• Time Format: HH:MM:SS (24 hr)
• Date Format: YY-MM-DD-dd
• Interface: Parallel
• Voltage - Supply: 4.5 V ~ 5.5 V
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Surface Mount
• Package / Case: 44-SOH
• Number Of Voltages Monitored: 1
• Monitored Voltage: 3.3 V, 5 V
• Manual Reset: Not Resettable
• Watchdog: Watchdog
• Battery Backup Switching: Backup
• Supply Voltage (max): 5.5 V
• Supply Voltage (min): 4.5 V
• Supply Current (typ): 15000 uA
• Maximum Power Dissipation: 1000 mW
• Maximum Operating Temperature: + 70 C
• Mounting Style: SMD/SMT
• Minimum Operating Temperature: 0 C
• Power Fail Detection: Yes
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Other names: 497-2840-5; M48T201Y-70MH1

Clock operation
Figure 8.
3.6
Note:
20/37
V CC
V PFD (max)
V PFD (min)
V SO
AFE bit/ABE bit
AF bit in Flags Register
IRQ/FT
Backup mode alarm waveforms
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 timeout into the Watchdog
Register, address 7FFF7h. 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 timeout 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).
Accuracy of timer is within ± the selected resolution.
If the processor does not reset the timer within the specified period, the M48T201Y/V sets
the WDF (watchdog flag) and generates a watchdog interrupt or a microprocessor reset.
WDF is reset by reading the flag register (address 7FFF0h).
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 pin when timed-out. When WDS is set to a
'1,' the watchdog will output a negative pulse on the RST pin for t
and the AFE, SQWE, ABE, and FT bits will reset to a '0' at the end of a watchdog timeout
when the WDS bit is set to a '1.'
The watchdog timer can be reset by two methods:
1.
2.
The timeout period then starts over. The WDI pin should be tied to V
watchdog will be reset on each transition (edge) seen by the WDI pin.
a transition (high-to-low or low-to-high) can be applied to the watchdog input pin (WDI)
or
the microprocessor can perform a WRITE of the watchdog register.
HIGH-Z
REC
. The watchdog register
M48T201Y, M48T201V
SS
if not used. The
AI03520
tREC
HIGH-Z