DS2174

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Mode Select

The DS2174 is configured to operate in bit, nibble, or byte mode by using the MODE1/MODE0 bits in

Control Register 2.

Table 3-1. MODE SELECT

MODE1

MODE0

OPERATION MODE

0

0

Bit

0

1

Nibble

1

0

Byte

1

1

Invalid

Error Insertion

The DS2174 inserts bit errors at a particular rate by setting the error insertion bits in Control Register 2

(Table 4). In addition, the device inserts errors on command by setting the SBE bit in Control Register 2.

The bit that occurs after the rising edge of the SBE insert bit is inverted. In the case of the QRSS pattern,

this could result in a string of 0’s longer than 14 bits; the DS2174 delays the erred bit by 1 clock cycle.

Data in the nibble and byte modes is presented 4 or 8 bits at a time. When in nibble or byte mode and

selecting 10

selecting an error rate of 10

Table 3 -2. ERROR BIT INSERTION

EIR2

EIR1

EIR0

ERROR RATE

SERIAL

NIBBLE

BYTE

0

0

0

None

4

4

4

0

0

1

10

-1

4

8

-1

8

-1

0

1

0

10

-2

4

4

8

-2

0

1

1

10

-3

4

4

4

1

0

0

10

-4

4

4

4

1

0

1

10

-5

4

4

4

1

1

0

10

-6

4

4

4

1

1

1

10

-7

4

4

4