TUSB1310

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SLLSE16B – DECEMBER 2009 – REVISED JUNE 2010

3.4.2

Receiver Detection

TX_DETRX_LPBK starts a receiver detection operation to determine if there is a receiver at the other end

of the link. When the receiver detect sequence completes, the PHY_STATUS is asserted for one clock

and drives the RX_STATUS signals to the appropriate code. Once the TX_DETRX_LPBK signal is

asserted, the link layer controller must leave the signal asserted until the PHY_STATUS pulse. When

receiver detection is performed in P3, the PHY_STATUS shows the appropriate receiver detect value until

the TX_DETRX_LPBK is de-asserted.

Table 3-5. RX_STATUS - Receiver Detection

RX_STATUS2-0

DETECTED CONDITION

LENGTH

000b

Receiver not present

One clock cycle

011b

Receiver present

3.4.3

8b/10b Decode Errors

When the TUSB1310 detects an 8b/10b decode error, it will assert an EDB (0xFE) symbol in the data on

the RX_DATA where the bad byte occurred. In the same clock cycle that the EDB symbol is asserted on

the RX_DATA, the 8b/10b decode error code (100b) will be asserted on the RX_STATUS. 8b/10b

decoding error has priority over all other receiver error codes and could mask out a disparity error

occurring on the other byte of data being clocked onto the RX_DATA with the EDB symbol.

Table 3-6. 8b/10b Decode Errors

RX_STATUS2-0

DETECTED ERROR

LENGTH

Clock cycles during the effected byte is

100b

8B/10B decode error

transferred on RX_DATA15-0

3.4.4

Elastic Buffer Errors

When the elastic buffer overflows, data is lost during the reception of the data. The elastic buffer overflow

error code (101b) will be asserted on the RX_STATUS on the PCLK cycle the omitted data would have

been asserted. The data asserted on the RX_DATA is still valid data, the elastic buffer overflow error code

on the RX_STATUS just marks a discontinuity point in the data stream being received.

When the elastic buffer underflows, EDB (0xFE) symbols are inserted into the data stream on the

RX_DATA to fill the holes created by the gaps between valid data. For every PCLK cycle a EDB symbol is

asserted on the RX_DATA, an elastic buffer underflow error code (111b) is asserted on the RX_STATUS.

In nominal empty buffer mode, SKP ordered sets are transferred on RX_DATA and the underflow is not

signaled.

Table 3-7. Elastic Buffer Errors

RX_STATUS2-0

DETECTED ERROR

LENGTH

Clock cycles the omitted data would have

101b

Elastic buffer overflow

appeared

Clock cycles during the EDB symbol

110b

Elastic buffer underflow

presence on RX_DATA15-0

3.4.5

Disparity Errors

When the TUSB1310 detects a disparity error, it will assert a disparity error code (111b) on the

RX_STATUS in the same PCLK cycle it asserts the erroneous data on the RX_DATA. The disparity code

does not discern which byte on the RX_DATA is the erroneous data.

Copyright © 2009–2010, Texas Instruments Incorporated

FUNCTIONAL DESCRIPTION

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