From 8aba99eb2d231c2cb4d4c2d9aa1eec5e17442fe6 Mon Sep 17 00:00:00 2001
From: Eric Kooistra <kooistra@astron.nl>
Date: Tue, 25 Oct 2022 17:27:28 +0200
Subject: [PATCH] Need sync_reg2 to align latency monitor when ref_sync =
in_sosi.sync.
---
libraries/base/dp/src/vhdl/dp_bsn_monitor_v2.vhd | 11 +++++++----
1 file changed, 7 insertions(+), 4 deletions(-)
diff --git a/libraries/base/dp/src/vhdl/dp_bsn_monitor_v2.vhd b/libraries/base/dp/src/vhdl/dp_bsn_monitor_v2.vhd
index 78249aab75..fd3981df8e 100644
--- a/libraries/base/dp/src/vhdl/dp_bsn_monitor_v2.vhd
+++ b/libraries/base/dp/src/vhdl/dp_bsn_monitor_v2.vhd
@@ -104,6 +104,7 @@ ARCHITECTURE rtl OF dp_bsn_monitor_v2 IS
SIGNAL nxt_valid : STD_LOGIC;
SIGNAL sop : STD_LOGIC;
SIGNAL nxt_sop : STD_LOGIC;
+ SIGNAL sync_reg2 : STD_LOGIC;
SIGNAL sync_reg : STD_LOGIC;
SIGNAL sync : STD_LOGIC;
SIGNAL nxt_sync : STD_LOGIC;
@@ -163,7 +164,7 @@ BEGIN
nxt_mon_nof_sop <= nof_sop WHEN sync='1' ELSE i_mon_nof_sop;
nxt_mon_nof_err <= nof_err WHEN sync='1' ELSE i_mon_nof_err;
nxt_mon_nof_valid <= nof_valid WHEN sync='1' ELSE i_mon_nof_valid;
- nxt_mon_latency <= latency WHEN sync_reg='1' ELSE i_mon_latency; -- use sync_reg due to ref_sync_reg
+ nxt_mon_latency <= latency WHEN sync_reg2='1' ELSE i_mon_latency; -- use sync_reg2 due to ref_sync_reg
nof_sop <= cnt_sop;
nof_err <= cnt_err;
@@ -171,9 +172,9 @@ BEGIN
latency <= cnt_latency;
-- Register ref_sync to ease timing closure for ref_sync fanout to (many) dp_bsn_monitor_v2
- -- instances. The ref_sync_reg is used to restart cnt_latency. Therefore the sync_reg
- -- (instead of sync) is needed to capture latency (= cnt_latency) not too early, so capture
- -- cnt_latency at or after the cnt_latency has restarted.
+ -- instances. The ref_sync_reg is used to restart cnt_latency. Therefore the sync_reg2
+ -- (instead of sync) is needed to capture latency (= cnt_latency) not too early, in case
+ -- ref_sync = in_sosi.sync, so capture cnt_latency at or after the cnt_latency has restarted.
ref_sync_reg <= ref_sync WHEN rising_edge(clk);
u_sync_timeout_cnt : ENTITY common_lib.common_counter
@@ -216,6 +217,7 @@ BEGIN
err <= '0';
sync <= '0';
sync_reg <= '0';
+ sync_reg2 <= '0';
bsn <= (OTHERS=>'0');
-- output
mon_evt <= '0';
@@ -237,6 +239,7 @@ BEGIN
err <= nxt_err;
sync <= nxt_sync;
sync_reg <= sync;
+ sync_reg2 <= sync_reg;
bsn <= nxt_bsn;
-- output
mon_evt <= nxt_mon_evt;
--
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