From 5545f12e817e8d97950a3cba38031479035029f6 Mon Sep 17 00:00:00 2001
From: Romain Broucquart <romain.broucquart@synchrotron-soleil.fr>
Date: Wed, 23 Mar 2022 08:35:47 +0100
Subject: [PATCH] Change CRC state machine
* Do not allow to start CRC computation right after a result
* CRC word counter up to 12 then roll over to 0
---
hdl/combpm_protocol_electron.vhd | 30 ++++++++++++++++--------------
1 file changed, 16 insertions(+), 14 deletions(-)
diff --git a/hdl/combpm_protocol_electron.vhd b/hdl/combpm_protocol_electron.vhd
index 636a385..8a383f9 100644
--- a/hdl/combpm_protocol_electron.vhd
+++ b/hdl/combpm_protocol_electron.vhd
@@ -178,23 +178,25 @@ begin
crc_reg <= C_CRCINIT;
crc_cnt <= (others => '0');
elsif rising_edge(clk) then
- if crc_cnt = 0 then
- if flag_sop_inc = '1' then
+ case crc_cnt is
+ when "0000" =>
+ if flag_sop_inc = '1' then
+ crc_cnt <= crc_cnt+1;
+ crc_reg <= C_CRCINIT;
+ else
+ crc_cnt <= (others => '0');
+ end if;
+ when "1011" =>
+ crc_reg <= crc_reg;
crc_cnt <= crc_cnt+1;
- crc_reg <= C_CRCINIT;
- else
- crc_cnt <= (others => '0');
- end if;
- else
- if crc_cnt = 10 then
+ when "1100" =>
+ crc_reg <= crc_reg;
crc_cnt <= (others => '0');
- else
- crc_cnt <= crc_cnt +1;
- end if;
- crc_reg <= lfsr_c;
-
+ when others =>
+ crc_reg <= lfsr_c;
+ crc_cnt <= crc_cnt+1;
+ end case;
- end if;
end if;
end process p_crc;
--
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