From fadf06530e31a517c277b5f5488ce2fb432c76b4 Mon Sep 17 00:00:00 2001
From: Eric Kooistra <kooistra@astron.nl>
Date: Wed, 4 Aug 2021 16:06:16 +0200
Subject: [PATCH] Fixed out_sosi.sync now starts with long fractional interval.
Added fast forward of next output_sync_bsn in case of lost blocks.
---
.../base/dp/src/vhdl/dp_bsn_sync_interval.vhd | 84 +++++++++++++------
1 file changed, 59 insertions(+), 25 deletions(-)
diff --git a/libraries/base/dp/src/vhdl/dp_bsn_sync_interval.vhd b/libraries/base/dp/src/vhdl/dp_bsn_sync_interval.vhd
index 84ab7eb94b..a3bb5f9c11 100644
--- a/libraries/base/dp/src/vhdl/dp_bsn_sync_interval.vhd
+++ b/libraries/base/dp/src/vhdl/dp_bsn_sync_interval.vhd
@@ -126,16 +126,19 @@ ARCHITECTURE rtl OF dp_bsn_sync_interval IS
blk_cnt : NATURAL;
interval_size : NATURAL;
start_bsn : STD_LOGIC_VECTOR(g_bsn_w-1 DOWNTO 0);
+ input_bsn : STD_LOGIC_VECTOR(g_bsn_w-1 DOWNTO 0);
nof_blk_min : NATURAL;
nof_blk_max : NATURAL;
- fraction_size : INTEGER RANGE -g_block_size TO g_block_size;
+ nof_blk : NATURAL;
+ extra : INTEGER;-- RANGE -g_block_size TO g_block_size;
+ accumulate : INTEGER;-- RANGE -g_block_size TO g_block_size;
hold_eop : STD_LOGIC;
update_bsn : STD_LOGIC;
output_enable : STD_LOGIC;
output_sync_bsn : STD_LOGIC_VECTOR(g_bsn_w-1 DOWNTO 0);
END RECORD;
- CONSTANT c_reg_rst : t_reg := ('0', '0', 0, 0, (OTHERS=>'0'), 0, 0, 0, '1', '0', '0', (OTHERS=>'0'));
+ CONSTANT c_reg_rst : t_reg := ('0', '0', 0, 0, (OTHERS=>'0'), (OTHERS=>'0'), 0, 0, 0, 0, 0, '1', '0', '0', (OTHERS=>'0'));
-- Local registers
SIGNAL r : t_reg;
@@ -177,25 +180,33 @@ BEGIN
-- Initialization: calculate number of blocks per output sync interval
IF r.enable_init = '1' THEN
- -- Assume ctrl_start_bsn more than nof_blk block periods is after the
- -- ctrl_enable_evt, so there is sufficient time until v.output_enable =
- -- '1', to perform the calculation of nof_blk_min and nof_blk_max
- -- sequentially. This avoids using division to calculate
- -- ctrl_interval_size / g_block_size.
+ -- Assume ctrl_start_bsn is scheduled more than nof_blk block clk cycles
+ -- after the ctrl_enable_evt, so there is sufficient time until
+ -- v.output_enable = '1', to perform the calculation of nof_blk_min and
+ -- nof_blk_max sequentially. This avoids using division in logic to
+ -- calculate ctrl_interval_size / g_block_size.
v_size := r.blk_cnt * g_block_size;
IF v_size = ctrl_interval_size THEN
+ -- Support integer number of blocks per output sync interval
v.interval_size := ctrl_interval_size; -- hold ctrl_interval_size
v.start_bsn := ctrl_start_bsn; -- hold ctrl_start_bsn
- v.nof_blk_min := r.blk_cnt; -- support integer number of blocks per output sync interval
+ -- Fixed sync interval control, effectively disable fractional sync interval control:
+ v.nof_blk_min := r.blk_cnt;
v.nof_blk_max := r.blk_cnt;
- v.fraction_size := 0; -- = nof_blk_max - nof_blk_min
+ v.nof_blk := r.blk_cnt; -- nof_blk = nof_blk_max = nof_blk_min
+ v.extra := 0;
+ v.accumulate := 0;
v.enable_init := '0'; -- enable initialization is done
ELSIF v_size > ctrl_interval_size THEN
+ -- Support fractional number of blocks per output sync interval
v.interval_size := ctrl_interval_size; -- hold ctrl_interval_size
v.start_bsn := ctrl_start_bsn; -- hold ctrl_start_bsn
- v.nof_blk_min := r.blk_cnt - 1; -- support fractional number of blocks per output sync interval
+ -- Fractional sync interval control:
+ v.nof_blk_min := r.blk_cnt - 1;
v.nof_blk_max := r.blk_cnt;
- v.fraction_size := v_size - ctrl_interval_size; -- number of extra samples in nof_blk_max
+ v.nof_blk := r.blk_cnt; -- start with nof_blk_max sync interval
+ v.extra := v_size - ctrl_interval_size; -- number of extra samples in nof_blk_max compared to ctrl_interval_size
+ v.accumulate := v.extra; -- start with nof_blk_max sync interval
v.enable_init := '0'; -- enable initialization is done
ELSE
v.blk_cnt := r.blk_cnt + 1;
@@ -211,8 +222,8 @@ BEGIN
v.enable := '1';
END IF;
- -- Hold eop to detect when input has finished a block and to detect gaps
- -- between in_sosi.eop and in_sosi.sop
+ -- Hold input eop to detect when input has finished a block and to detect
+ -- gaps between in_sosi.eop and in_sosi.sop
IF in_sosi.sop = '1' THEN
v.hold_eop := '0';
END IF;
@@ -220,16 +231,17 @@ BEGIN
v.hold_eop := '1';
END IF;
- -- Output enable at sync and disable after in_sosi.eop
IF r.enable = '1' THEN
+ -- Output enable at in_sosi.sop start_bsn
IF in_sosi.sop = '1' THEN
IF UNSIGNED(in_sosi.bsn) = UNSIGNED(r.start_bsn) THEN
v.output_enable := '1';
output_start <= '1'; -- Pulse at start of output enable at start BSN of output sync intervals
- v.output_sync_bsn := r.start_bsn;
+ v.output_sync_bsn := r.start_bsn; -- Initialize output sync at start BSN of output sync intervals
END IF;
END IF;
ELSE
+ -- Output disable after in_sosi.eop
IF r.hold_eop = '1' THEN
v.output_enable := '0';
END IF;
@@ -252,19 +264,41 @@ BEGIN
-- Determine BSN for next output sync
IF r.update_bsn = '1' THEN
- IF r.fraction_size > 0 THEN
- v.output_sync_bsn := ADD_UVEC(r.output_sync_bsn, TO_UVEC(r.nof_blk_min, c_natural_w)); -- next BSN
- v_size := r.nof_blk_min * g_block_size; -- next interval size
- ELSE
- v.output_sync_bsn := ADD_UVEC(r.output_sync_bsn, TO_UVEC(r.nof_blk_max, c_natural_w)); -- next BSN
- v_size := r.nof_blk_max * g_block_size; -- next interval size
+ -- Similar code as in proc_dp_verify_sync(), the difference is that:
+ -- . Here r.extra is number of extra samples in nof_blk_max compared to
+ -- ctrl_interval_size,
+ -- . in proc_dp_verify_sync() r.extra is number of extra samples in
+ -- ctrl_interval_size compared to nof_blk_min.
+ -- Both schemes are valid, by using different schemes here and in tb the
+ -- verification coverage improves.
+ v.output_sync_bsn := ADD_UVEC(r.output_sync_bsn, TO_UVEC(r.nof_blk, c_natural_w)); -- next BSN
+
+ v.nof_blk := r.nof_blk_max;
+ v.accumulate := r.accumulate + r.extra; -- account for nof_blk_max
+ IF v.accumulate >= g_block_size THEN
+ v.nof_blk := r.nof_blk_min;
+ v.accumulate := v.accumulate - g_block_size; -- adjust for nof_blk_min
END IF;
- v.fraction_size := r.fraction_size + v_size - ctrl_interval_size; -- next fraction
- -- Assume output_sync_bsn is in future, else next in_sosi.sop will
- -- result in a new update_bsn reqest, to catch up for lost input
- -- blocks.
+ -- Assume output_sync_bsn is in future
v.update_bsn := '0';
+
+ -- else last r.input_bsn will be used to keep update_bsn active for
+ -- more clk cycles to catch up for lost input blocks.
+ END IF;
+
+ -- Hold input bsn
+ IF in_sosi.sop = '1' THEN
+ v.input_bsn := in_sosi.bsn(g_bsn_w-1 DOWNTO 0);
+ END IF;
+
+ -- Catch up with output_sync_bsn in case of lost input blocks
+ IF v.output_enable = '1' THEN
+ IF UNSIGNED(r.input_bsn) > UNSIGNED(v.output_sync_bsn) THEN
+ -- Missed one or more input blocks, fast forward to look for next
+ -- output_sync_bsn
+ v.update_bsn := '1';
+ END IF;
END IF;
nxt_r <= v;
--
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