m41t62 STMicroelectronics, m41t62 Datasheet - Page 12

• Manufacturer Part Number: m41t62
• Description: Serial Access Real-time Clock With Alarms
• Manufacturer: STMicroelectronics

Operation
2
2.1
2.1.1
2.1.2
2.1.3
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Operation
The M41T6x clock operates as a slave device on the serial bus. Access is obtained by
implementing a start condition followed by the correct slave address (D0h). The 16 Bytes
contained in the device can then be accessed sequentially in the following order:
2-wire bus characteristics
The bus is intended for communication between different ICs. It consists of two lines: a bi-
directional data signal (SDA) and a clock signal (SCL). Both the SDA and SCL lines must be
connected to a positive supply voltage via a pull-up resistor.
The following protocol has been defined:
Accordingly, the following bus conditions have been defined:
Bus not busy
Both data and clock lines remain High.
Start data transfer
A change in the state of the data line, from high to Low, while the clock is High, defines the
START condition.
Stop data transfer
A change in the state of the data line, from Low to High, while the clock is High, defines the
STOP condition.
1
2
3
4
5
6
7
8
9
10
11
16th Byte: flags register
Data transfer may be initiated only when the bus is not busy.
During data transfer, the data line must remain stable whenever the clock line is High.
Changes in the data line, while the clock line is High, will be interpreted as control
signals.
st
nd
rd
th
th
th
th
th
th
th
th
Byte: tenths/hundredths of a second register
Byte: hours register
Byte: square wave/day register
Byte: date register
Byte: century/month register
Byte: year register
Byte: calibration register
Byte: minutes register
Byte: seconds register
Byte: watchdog register
- 15
th
Bytes: alarm registers
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