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AR# 14968

LogiCORE SPI-4.2 (POS-PHY L4) - Description of Error and Control Signals

Description

Keyword: PL4, POS, PHY, level, sink, source, packet, over, sonnet, DIP, SnkFFErr, SnkBusErr

The following Error and Control Signal descriptions augment the POS-PHY L4 data sheet information:

SnkBusErr

SnkFFErr

SnkFFPayloadErr

SnkFFDIP4Err

SnkOverflo_n

PhaseAlignErr

SnkOof

SrcDIP2Err

SrcPaternErr

SrcFFErr

SrcOof

SnkFFValid

Solution

SINK CORE

PhaseAlignErr??

Please refer to the data sheet:

http://www.xilinx.com/ipcenter/catalog/logicore/docs/spi4_2_product_spec.pdf

SnkOof??

Please refer to the data sheet:

http://www.xilinx.com/ipcenter/catalog/logicore/docs/spi4_2_product_spec.pdf

SnkBusErr??

This error can be triggered by five different conditions:

1. A reserved word was received.

2. A DIP4 error is not associated with a data word (i.e., something that would not be written into the FIFO, such as a DIP4 error on training, idle, etc.).

3. A payload control word is followed immediately by another payload control word.

4. An EOP is followed immediately by another EOP.

5. A burst was terminated on a non-credit boundary without an EOP.

This signal is not associated with any packet, but rather is asserted High for one cycle when any of the above conditions exist. If two (or more) back-to-back payload control words are received, the last one received is used and the others are discarded. If two (or more) back-to-back EOPs are received, the first one is used and the others are discarded.

The PL4 Sink core does not drop any data--it passes both valid and erroneous data words through the FIFO to the user. The Sink core uses SnkFFPayloadErr to flag packets that should be discarded. SnkBusErr is primarily used for tagging invalid PL4 control transitions not associated with data words (that is, DIP4 errors during training/idle, reserved words, control word violations, etc.). These are not written into the FIFO, so they are independently flagged with the SnkBusErr signal.

The only exception to this is a packet that does not end on a burst and is not terminated with an EOP. This currently flags a SnkBusErr, but causes neither an EOP Abort (seen on SnkFFErr) nor SnkBurstErr. Starting with SPI-4.2 v6.0 core, the sink core has been modified to flag SnkBusErr and SnkFFBurstErr which is asserted synchronous to SnkFFData.

In coming out of fifo reset state (de-assertion of Reset_n and SnkFifoReset_n), the sink core will discard all data on the SPI-4.2 interface until a valid SOP control word is received. This is the only case where data is discarded by the sink core.

SnkFFErr??

This is an "EOP Abort," as described in the data sheet:

http://www.xilinx.com/ipcenter/catalog/logicore/docs/spi4_2_product_spec.pdf

SnkFFPayloadErr??

This is asserted High when data is received without a valid payload control word preceding it. In this case, as a payload control word is not present, the address, SOP, etc. are unclear, and the error is flagged. This is asserted High with each data word that comes from the FIFO, and it will remain High until a valid payload control word followed by appropriate data is received. If SnkFFPayloadErr is High, you may discard this data.

SnkFFDIP4Err??

This is a DIP4 error that occurs over a data packet. When a DIP4 error occurs, it is assumed to be related to the preceding packet, not the next packet. This assumption could potentially be incorrect if the SOP or address of the next packet is corrupted.

SnkOverflow_n??

The Sink FIFO has overflown. In this case, data will be lost, because no more data will be written into the FIFO until it is not in an overflow state.

SnkFFValid??

Please refer to the data sheet:

http://www.xilinx.com/ipcenter/catalog/logicore/docs/spi4_2_product_spec.pdf

SOURCE CORE

SrcDIP2Err??

Please refer to the data sheet:

http://www.xilinx.com/ipcenter/catalog/logicore/docs/spi4_2_product_spec.pdf

SrcPatternErr??

This indicates that an invalid pattern is written into the PL4 Source FIFO. Two conditions trigger this error signal:

1. The address is changed on a non-credit boundary, without an EOP. In this case, the remainder of that packet will be terminated with an EOP Abort and sent out on the PL4 bus.

2. The SrcFFMod signal is non-zero without an EOP. This will not trigger an EOP Abort, but is an indication that an invalid write was made.

SrcFFErr??

This is a request that an EOP Abort be sent out on the PL4 bus.

SrcOof??

Please refer to the data sheet:

http://www.xilinx.com/ipcenter/catalog/logicore/docs/spi4_2_product_spec.pdf

AR# 14968
Date Created 08/29/2007
Last Updated 12/15/2012
Status Active
Type General Article