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DS21Q55

marked as “double interrupt bits.” An interrupt will be produced when the condition occurs and when it clears.

6.4 Information Registers

Information registers operate the same as status registers except they cannot cause interrupts. They are all latched except for INFO7 and some of the bits in INFO5 and INFO6. INFO7 register is a read only register and it reports the status of the E1 synchronizer in real time. INFO7 and some of the bits in INFO6 and INFO5 are not latched and it is no t necessary to precede a read of these bits with a write.

6.5 Interrupt Information Registers

The Interrupt Information Registers provide an indication of which Status Registers (SR1 through SR9) are generating an interrupt. When an interrupt occurs, the host can read IIR1 and IIR2 to quickly identify which of the 9 status registers are causing the interrupt.

Register Name:

IIR1

Register Description:

Interrupt Information Register 1

Register Address:

14h

Bit #

Name

Default

7

6

5

4

3

2

1

0

SR8

SR7

SR6

SR5

SR4

SR3

SR2

SR1

0

0

0

0

0

0

0

0

Register Name:

IIR2

Register Description:

Interrupt Information Register 2

Register Address:

15h

Bit #

Name

Default

7

6

5

4

3

2

1

0

-

-

-

-

-

-

-

SR9

0

0

0

0

0

0

0

0

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Please contact telecom.support@dalsemi.com or search http://www.maxim-ic.com for updated

information.

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Maxim DS21Q55 specifications Interrupt Information Registers, IIR1, IIR2