Datasheet

DocID12615 Rev 8 35/56

M41T93 Clock operation

3.9 Square wave output

The M41T93 offers the user a programmable square wave function which is output on the

SQW pin. RS3-RS0 bits located in 13h establish the square wave output frequency. These

frequencies are listed in Table 10. Once the selection of the SQW frequency has been

completed, the SQW pin can be turned on and off under software control with the square

wave enable bit (SQWE) located in register 0Ah.

Note: If the SQWE bit is set to '1', and V

falls below the switchover (V

) voltage, the

squarewave output will be disabled.

Table 10. Square wave output frequency

Square wave bits Square wave

RS3 RS2 RS1 RS0 Frequency Units

0 0 0 0 None –

0 0 0 1 32.768 kHz

0 0 1 0 8.192 kHz

0 0 1 1 4.096 kHz

0 1 0 0 2.048 kHz

0 1 0 1 1.024 kHz

0 1 1 0 512 Hz

0 1 1 1 256 Hz

1 0 0 0 128 Hz

1 0 0 1 64 Hz

1 0 1 0 32 Hz

1 0 1 1 16 Hz

11008Hz

11014Hz

11102Hz

11111Hz