M48T58Y-70MH1F STMicroelectronics, M48T58Y-70MH1F Datasheet - Page 19

• Manufacturer Part Number: M48T58Y-70MH1F
• Description: IC TIMEKPR SRAM 64KBIT 5V 28SOIC
• Manufacturer: STMicroelectronics
• Series: Timekeeper®r
• Type: Clock/Calendar/NVSRAMr

Specifications of M48T58Y-70MH1F

• Memory Size: 64K (8K x 8)
• 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: 28-SOIC, 28-SOH (8.48mm Width)
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 497-4722-2

M48T58, M48T58Y
6.5
Note:
Note:
6.6
Note:
Battery low flag
The M48T58/Y automatically performs periodic battery voltage monitoring upon power-up.
The battery low flag (BL), bit D6 of the flags register 1FFDh, will be asserted high if the
internal or SNAPHAT
low enable (BLE) bit has been previously set to '1.' The BL flag will remain active until
completion of battery replacement and subsequent battery low monitoring tests.
If a battery low is generated during a power-up sequence, this indicates that the battery
voltage is below 2.5 V (approximately), which may be insufficient to maintain data integrity.
Data should be considered suspect and verified as correct. A fresh battery should be
installed.
The SNAPHAT top may be replaced while V
This will cause the clock to lose time during the interval the SNAPHAT
disconnected.
Battery monitoring is a useful technique only when performed periodically. The M48T58/Y
only monitors the battery when a nominal V
which require extensive durations in the battery back-up mode should be powered-up
periodically (at least once every few months) in order for this technique to be beneficial.
Additionally, if a battery low is indicated, data integrity should be verified upon power-up via
a checksum or other technique.
Century bit
Bit D5 and D4 of clock register 1FFCh contain the CENTURY ENABLE bit (CEB) and the
CENTURY bit (CB). Setting CEB to a '1' will cause CB to toggle, either from a '0' to '1' or
from '1' to '0' at the turn of the century (depending upon its initial state). If CEB is set to a '0,'
CB will not toggle.
The WRITE bit must be set in order to write to the CENTURY bit.
®
battery is found to be less than approximately 2.5 V and the battery
Doc ID 2412 Rev 7
CC
CC
is applied to the device. Thus applications
is applied to the device.
®
battery/crystal top is
Clock operations
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