AR# 50101

Description

Aurora 64B66B v6.2 does not support hot-plug applications with Virtex-6 GTH transceivers. This answer record gives guidance about how to make Aurora 64B66B work in hot-plug applications.

Solution

LINK_RESETlogicavailable inthe CLOCK_CORRECTION_CHANNEL_BONDING module can be leveraged to detect hot-plug conditions. These signals will get asserted when there is no valid_btf character receivedfora pre-determined number of cycles.This helps in detecting the cable un-plug condition. Connect the LINK_RESET signal to the RX_PCS_CDR_RESET_IN signal of the transceiver so that GTH is reset when there is a cable un-plug condition.

FollowingAurora modules need some modifications to acheive hot-plug.

1. CLOCK_CORRECTION_CHANNEL_BONDING
2. RX_GEARBOX
3. aurora_64b66b_v6_2_WRAPPER

1. CLOCK_CORRECTION_CHANNEL_BONDING:

//assign LINK_RESET = 2'h0;
assign LINK_RESET = {link_reset_1,link_reset_0};

2. RX_GEARBOX:

// assign `DLY hdr_valid = ( odd && ({doutb[65],doutb[64]} == 2'b10 || {doutb[65],doutb[64]} == 2'b01) ) ? 1'b1 :1'b0;
assign `DLY hdr_valid = odd ? 1'b1 : 1'b0;

3. aurora_64b66b_v6_2_WRAPPER:

Declare the following wires - rx_pcs_cdr_reset, link_reset_c, resetdone_i

wire rx_pcs_cdr_reset;
wire[1:0]link_reset_c;
wire resetdone_i;

Code Edits:

// assign gth_tx_reset_comb_i = !tx_pcs_resetdone_i | RESET;
// assign rx_gb_reset_i = rx_pcs_cdr_resetdone_i && !RXRESET_IN;
// assign not_rx_pcs_cdr_resetdone_i = !rx_pcs_cdr_resetdone_i;

assign gth_tx_reset_comb_i = !resetdone_i | RESET;
assign rx_gb_reset_i = resetdone_i && !RXRESET_IN;
assign not_rx_pcs_cdr_resetdone_i = !resetdone_i;
assign rx_pcs_cdr_reset = link_reset_c[0];
assign resetdone_i=rx_pcs_cdr_resetdone_i & tx_pcs_resetdone_i;

AURORA_64B66B_V6_2_QUAD #
(
// Simulation attributes
.QUAD_SIM_GTHRESET_SPEEDUP (SIM_GTHRESET_SPEEDUP)
)
quad2_aurora_64b66b_v6_2_i
(
..
..
.RX_PCS_CDR_RESET_IN (rx_pcs_cdr_reset),
);
RX_GEARBOX #
(
.SYNC_CHAR(64'h7CFF_FFFF_E5AC_A9E8)
)
rx_gb_i
(
..
..
.slip(1'b1)
);\
CLOCK_CORRECTION_CHANNEL_BONDING #
(
.CH_BOND_MAX_SKEW (2'b10),
.CH_BOND_MODE (CHAN_BOND_MODE_0)
)
cbcc_gth_i
(
..
..
.LINK_RESET(link_reset_c)
);

Attachments

Associated Attachments