diff --git a/libraries/base/dp/src/vhdl/dp_bsn_source_v2.vhd b/libraries/base/dp/src/vhdl/dp_bsn_source_v2.vhd
index 107073c4340d4e0f7ea3aa02911c7454dcac0e03..c1f1e2ec35c21e3a7074df6e7fc5e36553475a40 100644
--- a/libraries/base/dp/src/vhdl/dp_bsn_source_v2.vhd
+++ b/libraries/base/dp/src/vhdl/dp_bsn_source_v2.vhd
@@ -19,9 +19,11 @@
--
-------------------------------------------------------------------------------
--- Purpose :
+-- Author : P.Donker okt. 2020, added bsn_time_offset
+--
+-- Purpose :
-- Start a periodic block sync interval and maintain a block sequence
--- number
+-- number according to the PPS and BSN grid defined in [1].
-- Description:
-- When dp_on is low then all outputs are low. When dp_on is high, the
-- output sync starts pulsing after bsn_time_offset (in clk cycles) with
@@ -29,19 +31,25 @@
-- sop and eop will be active.
-- Alternatively, one can assert dp_on while dp_on_pps is high to
-- start the data path on the next PPS.
+-- The src_out.sync always happens at the src_out.sop.
+-- If nof_clk_per_sync / g_block_size is an integer than all src_out.sync
+-- intervals will have nof_clk_per_sync clk cycles, else nof_clk_per_sync
+-- is the average number of clock cycles between src_out.sync and then the
+-- number of blocks per sync intervals will vary between c_nof_block_hi
+-- and c_nof_block_lo.
-- The dp_on is asynchronous. The dp_bsn_source_v2 takes care that
-- src_out.valid starts with a src_out.sop and that src_out.valid can
-- only go low after a src_out.eop, to ensure that src_out only produces
-- complete sop-eop blocks that enter the subsequent processing.
--- The bs_start is active at the first src_out.sop after dp_on went high.
+-- The bs_restart is active at the first src_out.sop after dp_on went high.
-- Remarks:
-- . Starting the data path is only possible from the dp_off state, so one
-- has to disable (dp_on='0') the data path before restarting it.
-- . Effectively dp_on_status = src_out.valid, because when the BSN source
-- is on, then src_out.valid = '1' at every clk cycle.
--
--- author : P.Donker okt. 2020, added bsn_time_offset
---
+-- References:
+-- [1] https://support.astron.nl/confluence/display/L2M/L2+STAT+Decision%3A+Timing+in+Station
LIBRARY IEEE, common_lib;
USE IEEE.STD_LOGIC_1164.ALL;
@@ -70,7 +78,7 @@ ENTITY dp_bsn_source_v2 IS
nof_clk_per_sync : IN STD_LOGIC_VECTOR(c_word_w-1 DOWNTO 0) := TO_UVEC(g_nof_clk_per_sync, c_word_w);
bsn_init : IN STD_LOGIC_VECTOR(g_bsn_w-1 DOWNTO 0) := (OTHERS=>'0');
bsn_time_offset : IN STD_LOGIC_VECTOR(g_bsn_time_offset_w-1 DOWNTO 0) := (OTHERS=>'0');
- current_bsn_time_offset : OUT STD_LOGIC_VECTOR(g_bsn_time_offset_w-1 DOWNTO 0); -- output for monitoring purpose in test bench.
+ current_bsn_time_offset : OUT STD_LOGIC_VECTOR(g_bsn_time_offset_w-1 DOWNTO 0);
src_out : OUT t_dp_sosi -- only uses sync, bsn[], valid, sop and eop
);
@@ -81,6 +89,8 @@ ARCHITECTURE rtl OF dp_bsn_source_v2 IS
CONSTANT c_block_size_cnt_w : NATURAL := ceil_log2(g_block_size);
CONSTANT c_block_cnt_zero : STD_LOGIC_VECTOR(g_bsn_w-1 DOWNTO 0) := (OTHERS => '0');
+ CONSTANT c_nof_block_lo : NATURAL := g_nof_clk_per_sync / g_block_size;
+ CONSTANT c_nof_block_hi : NATURAL := ceil_div(g_nof_clk_per_sync, g_block_size);
-- The state machine starts synchronously via s_bsn_time_offset, s_dp_on_sop to s_dp_on, or it starts
-- directly to s_dp_on. When in dp_on it loops between s_dp_on and s_dp_on_eop for every block.
@@ -117,7 +127,7 @@ ARCHITECTURE rtl OF dp_bsn_source_v2 IS
SIGNAL i_current_bsn_time_offset : STD_LOGIC_VECTOR(g_bsn_time_offset_w-1 DOWNTO 0);
SIGNAL nxt_current_bsn_time_offset : STD_LOGIC_VECTOR(g_bsn_time_offset_w-1 DOWNTO 0);
-
+
SIGNAL nxt_clk_cnt : STD_LOGIC_VECTOR(c_word_w-1 DOWNTO 0);
SIGNAL clk_cnt : STD_LOGIC_VECTOR(c_word_w-1 DOWNTO 0);
SIGNAL nxt_sync : STD_LOGIC;
@@ -145,7 +155,6 @@ BEGIN
nxt_bsn_time_offset_cnt <= bsn_time_offset_cnt;
nxt_current_bsn_time_offset <= bsn_time_offset;
-
IF UNSIGNED(clk_cnt) = UNSIGNED(nof_clk_per_sync) - 1 THEN
nxt_clk_cnt <= (OTHERS=>'0');
nxt_sync <= '1'; -- will set src_out.sync on next src_out.sop
@@ -166,8 +175,8 @@ BEGIN
nxt_sync <= '1'; -- ensure issue sync at first sync interval for start at PPS.
IF pps = '1' THEN
nxt_bsn_time_offset_cnt <= (OTHERS=>'0');
- nxt_state <= s_bsn_time_offset;
- END IF;
+ nxt_state <= s_bsn_time_offset;
+ END IF;
ELSE
nxt_state <= s_dp_on_sop;
END IF;
@@ -219,7 +228,6 @@ BEGIN
END CASE;
END PROCESS;
-
p_clk : PROCESS(rst, clk)
BEGIN
IF rst='1' THEN
@@ -247,5 +255,3 @@ BEGIN
END PROCESS;
END rtl;
-
-