M41ST87WMX6 STMicroelectronics, M41ST87WMX6 Datasheet - Page 36

• Manufacturer Part Number: M41ST87WMX6
• Description: IC SUPERVISOR RTC 160X8 28-SOIC
• Manufacturer: STMicroelectronics
• Type: Clock/Calendar/Supervisorr

Specifications of M41ST87WMX6

• Memory Size: 160B
• Time Format: HH:MM:SS:hh (24 hr)
• Date Format: YY-MM-DD-dd
• Interface: I²C, 2-Wire Serial
• Voltage - Supply: 2.7 V ~ 3.6 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 28-SOIC, 28-SOH (8.48mm Width)
• Function: Clock/Calendar/Alarm/Timer Interrupt
• Rtc Memory Size: 160 Byte
• Supply Voltage (max): 3.6 V
• Supply Voltage (min): 2.7 V
• Maximum Operating Temperature: + 85 C
• Minimum Operating Temperature: - 40 C
• Mounting Style: SMD/SMT
• Rtc Bus Interface: Serial (2-Wire, I2C)
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 497-5370-5; M41ST87WMX6

Clock operation
3.5
Note:
36/54
Should the watchdog timer time-out, and the WDS bit is programmed to output an interrupt,
either a transition of the WDI pin, or a value of 00h needs to be written to the watchdog
register in order to clear the IRQ/OUT pin. This will also disable the watchdog function until
it is again programmed correctly. A READ of the flags register will reset the watchdog flag
(bit D7; register 0Fh) but does not clear the IRQ/OUT pin.
The watchdog function is automatically disabled upon power-up and the watchdog register
is cleared.
Square wave output
The M41ST87Y/W offers the user a programmable square wave function which is output on
the SQW/FT pin. RS3-RS0 bits located in 13h establish the square wave output frequency.
These frequencies are listed in
completed, the SQW/FT pin can be turned on and off under software control with the square
wave enable bit (SQWE) located in register 0Ah.
The SQW/FT output is programmable as an N-channel, open drain output driver, or a full-
CMOS output driver. By setting the square wave open drain bit (SQWOD) to a '1,' the output
will be configured as an open drain (with I
SQWOD is set to '0,' the output will be configured as full-CMOS (sink and source current as
specified in
When configured as open drain (SQWOD = '1'), the SQW/FT pin requires an external pull-
up resistor.
Table 9.
RS3
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
Table 17 on page
Square wave output frequency
RS2
Square wave bits
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
44).
Doc ID 9497 Rev 9
Table
RS1
9. Once the selection of the SQW frequency has been
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
OL
as specified in
RS0
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
Table 17 on page
Frequency
32.768
8.192
4.096
2.048
1.024
None
M41ST87Y, M41ST87W
512
256
128
64
32
16
8
4
2
1
Square wave
44). When
Units
kHz
kHz
kHz
kHz
kHz
Hz
Hz
Hz
Hz
Hz
Hz
Hz
Hz
Hz
Hz
–