DS2417 View Datasheet(PDF) - Dallas Semiconductor -> Maxim Integrated

Part Name

Description

View to exact match

DS2417

1-Wire Time Chip with Interrupt

Dallas Semiconductor -> Maxim Integrated 

1-WIRE CRC GENERATOR Figure 4

Polynomial = X8 + X5 + X4 + 1

DS2417

R

S

1ST

2ND

3RD

4TH

STAGE STAGE STAGE STAGE

X0

X1

X2

X3

5TH

STAGE

X4

6TH

7TH

8TH

STAGE STAGE STAGE

X5

X6

X7

X8

INPUT DATA

TIMEKEEPING

A 32.768kHz crystal oscillator is used as the time base for the real-time clock counter. The oscillator can

be turned on or off under software control. The oscillator must be on for the real-time clock to function.

The real-time clock counter is double buffered. This allows the master to read time without the data

changing while it is being read. To accomplish this, a snapshot of the counter data is transferred to a

read/write buffer, which the user accesses.

DEVICE CONTROL BYTE

The DS2417 can generate interrupt pulses to trigger activities that have to occur at regular intervals. The

selection of this interval and the on/off control of the 32.768kHz crystal oscillator are done through the

device control byte. This byte can be read and written through the Clock Function commands.

Device Control Byte

7

6

5

4

3

2

1

0

IE IS2 IS1 IS0 OSC OSC 0

0

Bit 0 - 1 0 No function

Bits 0 and 1 are hard-wired to read all 0’s.

Bit 2 - 3 OSC Oscillator Enable/Disable

These bits control/report whether the 32.768kHz crystal oscillator is running. If the oscillator is running,

both OSC bits will read 1. If the oscillator is turned off these bits will all read 0. When writing the

device control byte both occurrences of the OSC bit should have identical data. Otherwise, the value in

bit address 3 (bold) takes precedence.

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