From c7f2439501651b8b687d06fd564b3ab275a0776e Mon Sep 17 00:00:00 2001
From: Eric Kooistra <kooistra@astron.nl>
Date: Fri, 15 Apr 2022 11:32:21 +0200
Subject: [PATCH] Fit one packet in FIFO.
---
libraries/base/dp/src/vhdl/dp_block_from_mm_dc.vhd | 11 ++++++++---
1 file changed, 8 insertions(+), 3 deletions(-)
diff --git a/libraries/base/dp/src/vhdl/dp_block_from_mm_dc.vhd b/libraries/base/dp/src/vhdl/dp_block_from_mm_dc.vhd
index 71706eaeff..86189e162c 100644
--- a/libraries/base/dp/src/vhdl/dp_block_from_mm_dc.vhd
+++ b/libraries/base/dp/src/vhdl/dp_block_from_mm_dc.vhd
@@ -65,8 +65,13 @@ END dp_block_from_mm_dc;
ARCHITECTURE str OF dp_block_from_mm_dc IS
- CONSTANT c_packet_size : NATURAL := g_nof_data * g_data_size; -- 512 * 2 = 1024 words.
- CONSTANT c_fifo_size : NATURAL := c_packet_size * 2;
+ CONSTANT c_packet_size : NATURAL := g_nof_data * g_data_size;
+
+ -- Fit one packet in FIFO, and less than two, to avoid filling the FIFO with
+ -- multiple packets in case writing FIFO (mm_clk) is faster than reading
+ -- FIFO (dp_clk).
+ CONSTANT c_fifo_fill : NATURAL := c_packet_size;
+ CONSTANT c_fifo_size : NATURAL := c_packet_size + c_packet_size/2;
CONSTANT c_start_addr_w : NATURAL := c_natural_w;
CONSTANT c_delay_len : NATURAL := c_meta_delay_len;
@@ -152,7 +157,7 @@ BEGIN
g_bsn_w => g_bsn_w,
g_use_bsn => TRUE,
g_use_sync => TRUE,
- g_fifo_fill => c_packet_size,
+ g_fifo_fill => c_fifo_fill,
g_fifo_size => c_fifo_size
)
PORT MAP (
--
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