[Cryptech-Commits] [core/comm/fmc] 01/03: 2-cycle sys_req delay for modexps6, because block RAMs

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paul at psgd.org pushed a commit to branch master
in repository core/comm/fmc.

commit 2f11ecd913368bf955aed40d22901b9f4998e8cc
Author: Paul Selkirk <paul at psgd.org>
Date:   Sat Oct 31 22:38:53 2015 -0400

    2-cycle sys_req delay for modexps6, because block RAMs
---
 src/rtl/fmc_arbiter_cdc.v | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/src/rtl/fmc_arbiter_cdc.v b/src/rtl/fmc_arbiter_cdc.v
index 0eca0b1..63e65b5 100644
--- a/src/rtl/fmc_arbiter_cdc.v
+++ b/src/rtl/fmc_arbiter_cdc.v
@@ -113,12 +113,12 @@ module fmc_arbiter_cdc #
 
 
    //
-   // System Request 1-cycle delay to compensate registered mux delay in user-side logic
+   // System Request 2-cycle delay to compensate registered mux delay in user-side logic
    //
-   reg sys_req_dly = 1'b0;
+   reg  [ 1: 0] sys_req_dly     = 2'b00;
 
    always @(posedge sys_clk)
-     sys_req_dly <= sys_req;
+     sys_req_dly <= {sys_req_dly[0], sys_req};
 
    //
    // SYS_CLK -> FMC_CLK Acknowledge
@@ -131,7 +131,7 @@ module fmc_arbiter_cdc #
      (
       .src_clk(sys_clk),
       .src_din(sys_data_in),
-      .src_req(sys_req_dly),
+      .src_req(sys_req_dly[1]),
 
       .dst_clk(fmc_clk),
       .dst_dout(fmc_dout),