Intel® Arria® 10 Transceiver PHY User Guide

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ID 683617
Date 3/28/2022
Public
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3.9.2. PMA and PCS Bonding

PMA and PCS bonding reduces skew between both the PMA and PCS outputs within a group of channels.

For PMA bonding, either x6/xN or PLL feedback compensation bonding is used. For PCS bonding, some of the PCS control signals within the bonded group are skew aligned using dedicated hardware inside the PCS.

Figure 185. PMA and PCS Bonding

For PMA and PCS bonding, the concept of master and slave channels is used. One PCS channel in the bonded group is selected as the master channel and all others are slave channels. To ensure that all channels start transmitting data at the same time and in the same state, the master channel generates a start condition. This condition is transmitted to all slave channels. The signal distribution of this start condition incurs a two parallel clock cycle delay. Because this signal travels sequentially through each PCS channel, this delay is added per channel. The start condition used by each slave channel is delay compensated based on the slave channel's distance from the master channel. This results in all channels starting on the same clock cycle.

The transceiver PHY IP automatically selects the center channel to be the master PCS channel. This minimizes the total starting delay for the bonded group. For PLL feedback compensation bonding up to all channels on one side can be bonded if the master PCS channel is placed in the center of the bonded group.

Note: Because the PMA and PCS bonding signals travel through each PCS block, the PMA and PCS bonded groups must be contiguously placed. The channel order needs to be maintained when doing the pin assignments to the dedicated RX serial inputs and TX serial outputs (for example: PIN_BC7 and PIN_BC8 for GXBR4D_TX_CH0p and GXBR4D_TX_CH0n TX serial outputs). Channels need to be placed in an ascending order from bottom to top. Swapping of channels, when doing pin assignments, leads to errors.

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