M48T59Y-70MH1 STMicroelectronics, M48T59Y-70MH1 Datasheet - Page 12

• Manufacturer Part Number: M48T59Y-70MH1
• Description: Real Time Clock U 511-M48T59Y-70MH1E
• Manufacturer: STMicroelectronics

Specifications of M48T59Y-70MH1

• Function: Clock, Calendar, NV Timekeeping RAM, Watchdog Timer, Battery Backup, Alarm
• Rtc Memory Size: 8192 B
• Supply Voltage (max): 5.5 V
• Supply Voltage (min): 4.5 V
• Maximum Operating Temperature: + 70 C
• Minimum Operating Temperature: 0 C
• Mounting Style: SMD/SMT
• Rtc Bus Interface: Parallel
• Package / Case: SOIC-28
• Time Format: HH:MM:SS
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

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3.1
3.2
Note:
3.3
Note:
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Clock operations
Reading the clock
Updates to the TIMEKEEPER
prevent reading data in transition. The BiPORT™ TIMEKEEPER cells in the RAM array are
only data registers and not the actual clock counters, so updating the registers can be halted
without disturbing the clock itself.
Updating is halted when a '1' is written to the READ Bit, D6 in the Control register (1FF8h).
As long as a '1' remains in that position, updating is halted. After a halt is issued, the
registers reflect the count; that is, the day, date, and the time that were current at the
moment the halt command was issued.
All of the TIMEKEEPER registers are updated simultaneously. A halt will not interrupt an
update in progress. Updating is within a second after the bit is reset to a '0.'
Setting the clock
Bit D7 of the Control register (1FF8h) is the WRITE Bit. Setting the WRITE Bit to a '1,' like
the READ Bit, halts updates to the TIMEKEEPER registers. The user can then load them
with the correct day, date, and time data in 24 hour BCD format (see
Resetting the WRITE Bit to a '0' then transfers the values of all time registers (1FF9h-
1FFFh) to the actual TIMEKEEPER counters and allows normal operation to resume. After
the WRITE Bit is reset, the next clock update will occur within approximately one second.
See the Application Note AN923, “TIMEKEEPER Rolling Into the 21st Century” for
information on Century Rollover.
Upon power-up following a power failure, both the WRITE Bit and the READ Bit will be reset
to '0.'
Stopping and starting the oscillator
The oscillator may be stopped at any time. If the device is going to spend a significant
amount of time on the shelf, the oscillator can be turned off to minimize current drain on the
battery. The STOP Bit is the MSB of the seconds register. Setting it to a '1' stops the
oscillator. The M48T59/Y/V in the DIP package is shipped from STMicroelectronics with the
STOP Bit set to a '1.' When reset to a '0,' the M48T59/Y/V oscillator starts within one
second.
It is not necessary to set the WRITE Bit when setting or resetting the FREQUENCY TEST
Bit (FT), the STOP Bit (ST) or the CENTURY ENABLE Bit (CEB).
®
registers should be halted before clock data is read to
Table 5 on page
13).