V-Series Transceiver PHY IP Core User Guide

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

14.5.3. RX PMA Parameters

Note: For more information about the CDR circuitry, refer to the Receiver PMA Datapath section in the Transceiver Architecture in Arria V Devices .
Table 230.  RX PMA Parameters  

Parameter

Range

Description

Enable CDR dynamic reconfiguration

On/Off

When you turn this option On, you can dynamically change the data rate of the CDR circuit.

Number of CDR reference clocks

1–5

Specifies the number of reference clocks for the CDRs.

Selected CDR reference clock

0–4

Specifies the index of the selected CDR reference clock.

Selected CDR reference clock frequency

Device Dependent

Specifies the frequency of the clock input to the CDR.

PPM detector threshold

+/- 1000 PPM

Specifies the maximum PPM difference the CDR can tolerate between the input reference clock and the recovered clock.

Enable rx_pma_clkout port

On/Off

When you turn this option On, the RX parallel clock which is recovered from the serial received data is an output of the PMA.

Enable rx_is_lockedtodata port

On/Off

When you turn this option On, the rx_is_lockedtodata port is an output of the PMA.

Enable rx_is_lockedtoref port

On/Off

When you turn this option On, the rx_is_lockedtoref port is an output of the PMA.

Enable rx_set_lockedtodata and rx_set_locktoref ports

On/Off

When you turn this option On, the rx_set_lockedtdata and rx_set_lockedtoref ports are outputs of the PMA.

Enable rx_pma_bitslip_port

On/Off

When you turn this option On, the rx_pma_bitslip is an input to the core. The deserializer slips one clock edge each time this signal is asserted. You can use this feature to minimize uncertainty in the serialization process as required by protocols that require a datapath with deterministic latency such as CPRI.

Enable rx_seriallpbken port

On/Off

When you turn this option On, the rx_seriallpbken is an input to the core. When your drive a 1 on this input port, the PMA operates in serial loopback mode with TX data looped back to the RX channel.

The following table  lists the best case latency for the most significant bit of a word for the RX deserializer for the PMA Direct datapath. PMA Direct mode is supported for Arria V GT, ST, and GZ devices only.

Table 231.  Latency for RX Deserialization in Arria V Devices 

FPGA Fabric Interface Width

Arria V Latency in UI

8 bits

19

10 bits

23

16 bits

35

20 bits

43

64 bits

99

80 bits

123

The following table  lists the best- case latency for the LSB of the TX serializer for all supported interface widths for the PMA Direct datapath.

Table 232.  Latency for TX Serialization n Arria V Devices

FPGA Fabric Interface Width

Arria V Latency in UI

8 bits

43

10 bits

53

16 bits

67

20 bits

83

64 bits

131

80 bits

163

The following table shows the bits used for all FPGA fabric to PMA interface widths. Regardless of the FPGA Fabric Interface Width selected, all 80 bits are exposed for the TX and RX parallel data ports. However, depending upon the interface width selected not all bits on the bus will be active. The following table shows which bits are active for each FPGA Fabric Interface Width selection. For example, if your interface is 16 bits, the active bits on the bus are [17:0] and [7:0] of the 80 bit bus. The non-active bits are tied to ground.

Table 233.  Active Bits for Each Fabric Interface Width

FPGA Fabric Interface Width

Bus Bits Used

8 bits

[7:0]

10 bits

[9:0]

16 bits

{[17:10], [7:0]}

20 bits

[19:0]

40 bits

[39:0]

64 bits

{[77:70], [67:60], [57:50], [47:40], [37:30], [27:20], [17:10], [7:0]}

80 bits

[79:0]