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authorMatt Ettus <matt@ettus.com>2010-11-11 18:50:49 -0800
committerMatt Ettus <matt@ettus.com>2010-11-11 18:50:49 -0800
commit78abd7d98a5dc42aeafa89ed29a3ab8a1f9475f4 (patch)
treed0fbe6c09fb381aa39551bf0d38f738b8f787472 /usrp2
parent12c8995014a625aab9a7614d9b146876fbf81268 (diff)
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gray code address for emi
Diffstat (limited to 'usrp2')
-rw-r--r--usrp2/extramfifo/nobl_if.v8
1 files changed, 7 insertions, 1 deletions
diff --git a/usrp2/extramfifo/nobl_if.v b/usrp2/extramfifo/nobl_if.v
index 7ff7eaa03..b5ebe9c6b 100644
--- a/usrp2/extramfifo/nobl_if.v
+++ b/usrp2/extramfifo/nobl_if.v
@@ -39,6 +39,12 @@ module nobl_if
assign RAM_LDn = 0;
// ZBT/NoBL RAM actually manages its own output enables very well.
assign RAM_OEn = 0;
+
+ // gray code the address to reduce EMI
+ wire [DEPTH-1:0] address_gray;
+
+ bin2gray #(.WIDTH(DEPTH)) bin2gray (.bin(address),.gray(address_gray));
+
//
// Pipeline stage 1
@@ -62,7 +68,7 @@ module nobl_if
if (enable)
begin
- address_pipe1 <= address;
+ address_pipe1 <= address_gray;
write_pipe1 <= write;
// RAM_WEn <= ~write; // Creates IOB flop