xbar and valve: fix switching delayed by active signal

2 files changed, 12 insertions, 9 deletions

diff --git a/usrp2/fifo/crossbar36.v b/usrp2/fifo/crossbar36.v
index d90f5659c..2a046d8bf 100644
--- a/usrp2/fifo/crossbar36.v
+++ b/usrp2/fifo/crossbar36.v
@@ -9,6 +9,8 @@ module crossbar36
    output [35:0] data1_o, output src1_rdy_o, input dst1_rdy_i);
 
    reg 		 cross_int, active0, active1;
+   wire active0_next = (src0_rdy_i & dst0_rdy_o)? ~data0_i[33] : active0;
+   wire active1_next = (src1_rdy_i & dst1_rdy_o)? ~data1_i[33] : active1;
 
    assign data0_o = cross_int ? data1_i : data0_i;
    assign data1_o = cross_int ? data0_i : data1_i;
@@ -22,19 +24,19 @@ module crossbar36
    always @(posedge clk)
      if(reset | clear)
        active0 <= 0;
-     else if(src0_rdy_i & dst0_rdy_o)
-       active0 <= ~data0_i[33];
+     else
+       active0 <= active0_next;
    
    always @(posedge clk)
      if(reset | clear)
        active1 <= 0;
-     else if(src1_rdy_i & dst1_rdy_o)
-       active1 <= ~data1_i[33];
+     else
+       active1 <= active1_next;
 
    always @(posedge clk)
      if(reset | clear)
        cross_int <= 0;
-     else if(~active0 & ~active1)
+     else if(~active0_next & ~active1_next)
        cross_int <= cross;
    
 endmodule // crossbar36
diff --git a/usrp2/fifo/valve36.v b/usrp2/fifo/valve36.v
index b4b23e5a6..d45eee497 100644
--- a/usrp2/fifo/valve36.v
+++ b/usrp2/fifo/valve36.v
@@ -7,7 +7,8 @@ module valve36
    output [35:0] data_o, output src_rdy_o, input dst_rdy_i);
    
    reg 		 shutoff_int, active;
-   
+   wire active_next = (src_rdy_i & dst_rdy_o)? ~data_i[33] : active;
+
    assign data_o = data_i;
 
    assign dst_rdy_o = shutoff_int ? 1'b1 : dst_rdy_i;
@@ -16,13 +17,13 @@ module valve36
    always @(posedge clk)
      if(reset | clear)
        active <= 0;
-     else if(src_rdy_i & dst_rdy_o)
-       active <= ~data_i[33];
+     else
+       active <= active_next;
    
    always @(posedge clk)
      if(reset | clear)
        shutoff_int <= 0;
-     else if(~active)
+     else if(~active_next)
        shutoff_int <= shutoff;
    
 endmodule // valve36