V-Series Transceiver PHY IP Core User Guide

ID 683171
Date 7/26/2022
Public
Document Table of Contents

16.6.7. Bit Reversal and Polarity Inversion

The bit reversal and polarity inversion functions allow you to reverse bit order, byte order, and polarity to correct errors and to accommodate different layouts of data.
Table 309.  Bit Reversal and Polarity Inversion Parameters 

Parameter

Range

Description

Enable TX bit reversal

On/Off

When you turn this option On, the word aligner reverses TX parallel data before transmitting it to the PMA for serialization. You can only change this static setting using the Transceiver Reconfiguration Controller.

Enable RX bit reversal

On/Off

When you turn this option On, the rx_std_bitrev_ena port controls bit reversal of the RX parallel data after it passes from the PMA to the PCS.

Enable RX byte reversal

On/Off

When you turn this option On, the word aligner reverses the byte order before transmitting data. This function allows you to reverse the order of bytes that were erroneously swapped. The PCS can swap the ordering of both 8 and10 bit words.

Enable TX polarity inversion

On/Off

When you turn this option On, the tx_std_polinv port controls polarity inversion of TX parallel data before transmitting the parallel data to the PMA.

Enable RX polarity inversion

On/Off

When you turn this option On, asserting rx_std_polinv controls polarity inversion of RX parallel data after PMA transmission.

Enable rx_std_bitrev_ena port

On/Off

When you turn this option On, asserting rx_std_bitrev_ena control port causes the RX data order to be reversed from the normal order, LSB to MSB, to the opposite, MSB to LSB. This signal is an asynchronous input.

Enable rx_std_byterev_ena port

On/Off

When you turn this option On, asserting rx_std_byterev_ena input control port swaps the order of the individual 8 or 10bit words received from the PMA.

Enable tx_std_polinv port

On/Off

When you turn this option On, the tx_std_polinv input is enabled. You can use this control port to swap the positive and negative signals of a serial differential link if they were erroneously swapped during board layout.

Enable rx_std_polinv port

On/Off

When you turn this option On, the rx_std_polinv input is enabled. You can use this control port to swap the positive and negative signals of a serial differential link if they were erroneously swapped during board layout.

Enable tx_std_elecidle port

On/Off

When you turn this option On, the tx_std_elecidle input port is enabled. When this signal is asserted, it forces the transmitter to electrical idle.

Enable rx_std_signaldetect port

On/Off

When you turn this option On, the optional rx_std_signaldetect output port is enabled. This signal is required for the PCI Express protocol. If enabled, the signal threshold detection circuitry senses whether the signal level present at the RX input buffer is above the signal detect threshold voltage that you specified.

For SATA / SAS applications, enable this port and set the following QSF assignments to the transceiver receiver pin:

  • set_instance_assignment -name XCVR_RX_SD_ENABLE ON
  • set_instance_assignment -name XCVR_RX_SD_THRESHOLD 7
  • set_instance_assignment -name XCVR_RX_COMMON_MODE_VOLTAGE VTT_OP55V
  • set_instance_assignment -name XCVR_RX_SD_OFF 1
  • set_instance_assignment -name XCVR_RX_SD_ON 2
Note: The above QSF assignments provide you an example, but the actual setting may vary as per the recommendations from the characterization report. You are also required to set up the platform device level pairing.

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