ADIN1111BCPZ-R7 datasheet(26/109 Pages) AD

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Data Sheet

ADIN1111

ON-CHIP DIAGNOSTICS

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Rev. A | 26 of 109

1. Read the PMA_PMD_STAT1 register (Device Address 0x01,

2. Check the PMA_LINK_STAT_OK bit (Bit 2, Mask 0x0004) val-

ue. If the bit value is 0, indicating the link is down, skip the

following steps and start over again. If the bit value is 1,

indicating link is up, continue with the following steps.

3. Read the MSE_VAL register (Device Address 0x01, Register

Address 0x830B).

4. Process/use the measured MSE.

MSE Interpretation

The easiest use of the measured MSE is to compare the value read

from the MSE_VAL register directly with the MSE register value

range and to interpret the link quality as outlined in Table 21 or

Table 22.

Alternatively, the MSE_VAL register value can be interpreted as the

MSE as follows:

MSEdB =10log10MSEVAL×1.5523218 (3)

And the SNR can be calculated as follows:

SNRdB =−10×log10MSEVAL×1.5523218 (4)

where:

1.5523 is a coefficient related to the 10BASE-T1L modulation and

symbol coding.

218 is a coefficient coming from the implementation of the on-chip

logic mapping the 16-bit register to a useful range.

Table 21. Link Quality vs. MSE Register Value

Link Quality

SNR (dB)

MSE Register Value Range

(hex)

BER

Poor

<19.5

>0x0766

>10−8

Marginal

19.5 to 20.5

0x05E1 to 0x0766

10−8 to 10−10

Good

>20.5

<0x05E1

<10−10

Table 22. Signal Quality Indicator vs. MSE Register Value

SQI

SNR (dB)

MSE Register Value Range (hex) BER

<18

>0x0A74

>10−7

18 to 19

0x084E to 0x0A74

>10−7

19 to 20

0x0698 to 0x084E

10−9 to 10−7

20 to 21

0x053D to 0x0698

10−11 to 10−9

21 to 22

0x0429 to 0x053D

10−14 to 10−11

22 to 23

0x034E to 0x0429

<10−14

23 to 24

0x02A0 to 0x034E

<10−14

>24

<0x02A0

<10−14

PHY Slicer Spikes and Errors

The MSE quantity provides an important tool to evaluate the link

quality and the effect of noise on the performance of the 10BASE-

T1L link. However, given that the MSE is taken as an average value

over a period, in cases where the interference is a short transient,

the value of the MSE may not reflect this. Yet, there may be enough

affectation on the received symbols to produce packet errors.

For this type of transient interference, the ADIN1100, ADIN1101,

ADIN1110, ADIN1111, and ADIN2111 include indicators that keep

track of the maximum slicer input error and the number of error

spikes at the input of the slicer. These indicators also offer the

advantage that can be read while there is a 10BASE-T1L link and

normal data flow. Thus, these indicators can be utilized to track the

link integrity before a hard fault occurs.

Slicer Maximum Absolute Error

As noted in the Mean Squared Error at PHY Slicer section, after the

received analog signal is processed, the slicer makes the decision

whether the received signal corresponds to a +1, 0, or −1 (PAM3

symbol). For instance, a processed received signal may have a

value of 0.8. Thus, the slicer outputs a +1 symbol, given that 0.8 is

closer to +1 than to 0 or −1. The closer the processed signal is to

the ideal symbol, the more reliable the communication is.

Figure 18 shows the received processed signals at the input of

the slicer and the corresponding ideal symbols at the output of

the slicer. Notice that the signal marked as 3 has a value of 0.4.

Therefore, the slicer outputs a 0 symbol and the actual error is 0.4.

If the error is greater than 0.5, the received signal is closer to a

+1 symbol than to its ideal 0 symbol. Thus, the slicer interprets the

symbol as a +1, producing a bit error in the received frame.

The slicer maximum absolute error must always be less than a

value of 0.5. Values close to 0.5 or greater than 0.5 indicate that the

received signal integrity has been affected.

Figure 18. Maximum Slicer Input Error

This maximum error can be tracked over time, before it reaches

0.5, to provide an early indication of link degradation.

Slicer Error Spike Counter

In addition to the maximum slicer absolute error, which only tracks

the absolute error of the most deviated symbol, the ADIN1100,

ADIN1101, ADIN1110, ADIN1111, and ADIN2111 keep track of the

number of received symbols with an absolute error greater than a

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