50G Interlaken MegaCore Function User Guide

ID 683217
Date 9/20/2022
Public

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7.3.1. Setting up PRBS Mode in Arria V and Stratix V Devices

To enable the IP core to generate PRBS output, you must program the relevant hard PCS registers to enable the PRBS generator clock, to set the test_enable bit, and to select the PRBS polynomial. To enable the IP core to receive PRBS input, you must program the relevant hard PCS registers to enable the PRBS receiver clock, to set the test_enable bit, and to select the expected PRBS polynomial. If you perform your PRBS testing in loopback mode, you must enable the IP core to both generate and receive PRBS sequences.

This section describes the register values you must program. For instructions to program the registers that activate the PRBS test feature in your Arria V or Stratix V 50G Interlaken IP core, refer to the hard PCS register programming instructions in the Native PHY IP Core chapter for your target device family and in the Transceiver Reconfiguration Controller chapter of the Intel® Transceiver PHY IP Core User Guide.

Table 21.  Programming the Hard PCS Registers in Arria V and Stratix V Devices

To turn on the PRBS feature in the hard PCS, you must program the following hard PCS registers in the order shown, for each of the TX and RX sides. These registers are not accessible using the 50G Interlaken IP core Management interface. You must access these registers through the Transceiver Reconfiguration Controller that connects to the IP core.

Ensure you set these register bits using a read-modify-write register access sequence (per register), to avoid modifying the other register fields.

TX Register Offset Bits Meaning Action
1 0x141 [0] Invert TX channels Set this bit to the value of 0 to specify that the outgoing PRBS be inverted, or set this bit to the value of 1 to specify that the outgoing PRBS not be inverted. The default value of this register bit is 0. By default, the outgoing PRBS is inverted.
2 0x135 [10] Enable PRBS7 Set one of these bits to the value of 1, and the others to the value of 0, to select the TX polynomial.
[8] Enable PRBS23
[6] Enable PRBS9
[4] Enable PRBS31
[3] TX test enable Set this bit to the value of 1 to enable the PRBS pattern generator in the transmitter.
3 0x137 [2] Enable TX PRBS clock Set this bit to the value of 1 to enable the TX PRBS clock.
RX Register Offset Bits Meaning Action
1 0x16D [2] Invert RX channels Set this bit to the value of 0 to specify that the PCS should expect the incoming PRBS to be inverted, or set this bit to the value of 1 to specify that the PCS should not expect the incoming PRBS to be inverted. The default value of this bit is 0. In loopback mode, you should set this bit to match the setting in the PRBS transmitter.
2 0x15E [14] Enable PRBS7 Set one of these bits to the value of 1, and the others to the value of 0, to select the expected polynomial.
[13] Enable PRBS23
[12] Enable PRBS9
[11] Enable PRBS31
[10] RX test enable Set this bit to the value of 1 to enable the PRBS pattern verifier in the receiver.
3 0x164 [10] Enable RX PRBS clock Set this bit to the value of 1 to enable the RX PRBS clock.

After you activate an IP core that targets an Arria V or Stratix V device to generate PRBS output, it immediately begins transmitting PRBS output on the Interlaken link. After you enable the IP core to receive PRBS input, you can check the receive PRBS status in the 50G Interlaken IP core PRBS status registers (RX_PRBS_DONE, RX_PRBS_ERR, and RX_PRBS_COUNT).

After your testing is complete, you must reset these register bits to their default values to enable normal operation.