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CTU CAN FD IP Core
Commit ff941cbf authored by Ille, Ondrej, Ing.'s avatar Ille, Ondrej, Ing.
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Re-factored busSync.

parent 3541a1a2
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Showing with 464 additions and 199 deletions
src/Bus_Timing_Synchronisation/busSync.vhd
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......@@ -84,7 +84,8 @@
-- Thus reading TRV_DELAY register would always result in tran-
-- sceiver delay of last CAN FD Frame. This is done to avoid
-- reading wrong value from TRV_DELAY register during measurment.
--
-- 10.12.2018 Re-factored, added generic Shift register instances. Added
-- generic synchronisation chain module.
--------------------------------------------------------------------------------
Library ieee;
......@@ -92,6 +93,7 @@ USE IEEE.std_logic_1164.all;
USE IEEE.numeric_std.ALL;
USE WORK.CANconstants.ALL;
use work.CAN_FD_register_map.all;
use work.cmn_lib.all;
entity busSync is
GENERIC (
......@@ -178,6 +180,29 @@ entity busSync is
-- Used only for bit error with secondary sample point
);
end entity;
architecture rtl of busSync is
-----------------------------------------------------------------------------
-- Internal constants declaration.
-----------------------------------------------------------------------------
-- Shift registers length
constant SSP_SHIFT_LENGTH : natural := 130;
constant TX_DATA_SHIFT_LENGTH : natural := 130;
-- Reset value for secondar sampling point shift registers
constant SSP_SHIFT_RST_VAL : std_logic_vector(SSP_SHIFT_LENGTH - 1
downto 0) :=
(OTHERS => '0');
constant TX_DATA_SHIFT_RST_VAL : std_logic_vector(TX_DATA_SHIFT_LENGTH - 1
downto 0) :=
(OTHERS => RECESSIVE);
-----------------------------------------------------------------------------
-- Driving bus aliases
......@@ -189,39 +214,48 @@ entity busSync is
-- Enable of the whole driver
signal drv_ena : std_logic;
-----------------------------------------------------------------------------
-- Internal registers and signals
-----------------------------------------------------------------------------
-- Synchronisation chain for data input (first,second and output register)
signal sync_Chain_1 : std_logic;
signal sync_Chain_2 : std_logic;
signal sync_Data : std_logic;
-- CAN RX synchronisation chain output
signal CAN_rx_synced : std_logic;
-- Shift registers length
constant shift_length : natural:=130;
-- Bus sampling and edge detection, Previously sampled value on CAN bus
signal prev_Sample : std_logic;
-- Internal received CAN Data. Selected between Raw input value and
-- synchronised value by signal synchroniser.
signal CAN_rx_i : std_logic;
-- Majority value from all three sampled values in tripple sampling shift
-- register
signal trs_majority : std_logic;
signal CAN_rx_trs_majority : std_logic;
-- CAN RX Data selected between normally sampled data (CAN_rx_i) and
-- Tripple sampled data!
signal data_rx_nbt : std_logic;
-- Bus sampling and edge detection, Previously sampled value on CAN bus
signal prev_Sample : std_logic;
-- Secondary sampling signal (sampling with transciever delay compensation)
signal sample_sec : std_logic;
signal sample_sec_comb : std_logic;
-- Secondary sample signal 1 and 2 clk_sys cycles delayed
signal sample_sec_del_1 : std_logic;
signal sample_sec_del_2 : std_logic;
-- Shift Register for storing the TX data for secondary sample point
signal ssp_shift : std_logic_vector
(shift_length - 1 downto 0);
signal tx_data_shift : std_logic_vector
(TX_DATA_SHIFT_LENGTH - 1 downto 0);
-- Delayed TX Data from TX Data shift register at position of secondary
-- sampling point.
signal tx_data_delayed : std_logic;
-- Shift Register for generating secondary sampling signal
signal sample_sec_shift : std_logic_vector
(shift_length - 1 downto 0);
(SSP_SHIFT_LENGTH - 1 downto 0);
-- Register for edge detection
signal edge_rx_det : std_logic;
......@@ -250,24 +284,39 @@ entity busSync is
signal trv_delay : std_logic_vector(6 downto 0);
--Delay compensation measuring is running (between tx edge and rx edge)
signal trv_running : std_logic;
signal trv_to_restart : std_logic;
end entity;
signal trv_meas_running : std_logic;
signal trv_meas_to_restart : std_logic;
architecture rtl of busSync is
begin
--Driving bus alias
---------------------------------------------------------------------------
-- Driving bus alias
---------------------------------------------------------------------------
drv_sam <= drv_bus(DRV_SAM_INDEX);
drv_ena <= drv_bus(DRV_ENA_INDEX);
--Synchronisation-chain enable
sync_Data <= sync_Chain_2 when use_Sync=true else
CAN_rx;
--Output data propagation
CAN_tx <= data_tx;
----------------------------------------------------------------------------
-- Synchronisation chain for input signal
----------------------------------------------------------------------------
can_rx_sig_sync_comp : sig_sync
port map(
clk => clk_sys,
async => CAN_rx,
sync => CAN_rx_synced
);
---------------------------------------------------------------------------
-- Synchronisation-chain selection
---------------------------------------------------------------------------
sync_chain_true : if (use_Sync = true) generate
CAN_rx_i <= CAN_rx_synced;
end generate;
sync_chain_false : if (use_Sync = false) generate
CAN_rx_i <= CAN_rx;
end generate;
----------------------------------------------------------------------------
......@@ -284,74 +333,75 @@ begin
elsif (rising_edge(clk_sys)) then
-- Do not propagate during the measurement!
if (trv_running = '0') then
if (trv_meas_running = '0') then
trv_delay_out <= "000000000" & trv_delay;
end if;
end if;
end process;
-- Registers to output propagation
sample_sec_out <= sample_sec;
sample_sec_del_1_out <= sample_sec_del_1;
sample_sec_del_2_out <= sample_sec_del_2;
-- Bit Error propagation
bit_Error <= bit_Error_reg;
---------------------------------------------------------------------------
-- Tripple sampling majority selection
---------------------------------------------------------------------------
trs_maj_dec_comp : majority_decoder_3
port map(
input => trs_reg,
output => CAN_rx_trs_majority
);
--Tripple sampling majority selection
trs_majority <= '1' when trs_reg = "110" else
'1' when trs_reg = "101" else
'1' when trs_reg = "011" else
'0' when trs_reg = "001" else
'0' when trs_reg = "010" else
'0' when trs_reg = "100" else
'0' when trs_reg = "000" else
'1' when trs_reg = "111" else
'1'; --When unknown rather climb to recessive
----------------------------------------------------------------------------
-- Synchronisation chain
----------------------------------------------------------------------------
sync_chain_proc : process(res_n, clk_sys)
begin
if (res_n = '0') then
sync_Chain_1 <= RECESSIVE;
sync_Chain_2 <= RECESSIVE;
elsif (rising_edge(clk_sys)) then
sync_Chain_1 <= CAN_rx;
sync_Chain_2 <= sync_Chain_1;
end if;
end process sync_chain_proc;
---------------------------------------------------------------------------
-- Selection of RX Data sampled in Nominal Bit-rate between Normally
-- sampled and tripple sampled data.
---------------------------------------------------------------------------
data_rx_nbt <= CAN_rx_trs_majority when (drv_sam = TSM_ENABLE) else
CAN_rx_i;
----------------------------------------------------------------------------
-- Data Edge detection (for one clk_sys period)
-- RX Data Edge detection (for one clk_sys period)
-- Note: Sucessful samplng of previous bit is necessary
-- (prev_Sample register)
----------------------------------------------------------------------------
edge_proc : process(res_n, clk_sys)
rx_edge_proc : process(res_n, clk_sys)
begin
if (res_n = ACT_RESET) then
edge_rx_det <= RECESSIVE;
edge_rx_valid <= '0';
edge_tx_det <= RECESSIVE;
edge_tx_valid <= '0';
elsif rising_edge(clk_sys) then
-- Rx data
edge_rx_det <= sync_Data;
edge_rx_det <= CAN_rx_i;
--Rx data edge appeared from recessive to dominant
if ((not edge_rx_det = sync_Data)and
(not prev_Sample = sync_Data) and (prev_Sample = RECESSIVE))
if ((not edge_rx_det = CAN_rx_i) and
(not prev_Sample = CAN_rx_i) and (prev_Sample = RECESSIVE))
then
edge_rx_valid <= '1';
else
edge_rx_valid <= '0';
end if;
end if;
end process rx_edge_proc;
----------------------------------------------------------------------------
-- TX Data Edge detection (for one clk_sys period)
----------------------------------------------------------------------------
tx_edge_proc : process(res_n, clk_sys)
begin
if (res_n = ACT_RESET) then
edge_tx_det <= RECESSIVE;
edge_tx_valid <= '0';
elsif rising_edge(clk_sys) then
-- Tx data
edge_tx_det <= data_tx;
--Tx data edge appeared from RECESSIVE to dominant
if ((not (edge_tx_det = data_tx)) and (edge_tx_det = RECESSIVE)) then
edge_tx_valid <= '1';
......@@ -360,91 +410,150 @@ begin
end if;
end if;
end process edge_proc;
-- Propagating edge value on output
sync_edge <= edge_rx_valid;
end process tx_edge_proc;
----------------------------------------------------------------------------
-- Measuring transciever delay compenstaion
-- Control for transceiver delay measurement.
----------------------------------------------------------------------------
trv_delay_proc : process(res_n, clk_sys)
begin
if (res_n = '0') then
trv_delay <= (OTHERS => '0');
trv_running <= '0';
trv_to_restart <= '0';
trv_meas_running <= '0';
trv_meas_to_restart <= '0';
elsif (rising_edge(clk_sys)) then
--------------------------------------------------------------------
-- Measuring of delay enabled
--------------------------------------------------------------------
-- Delay measurement enabled
if (trv_delay_calib = '1') then
----------------------------------------------------------------
-- Starting and stop the counter
----------------------------------------------------------------
-- Stop delay measurement upon receiving the edge on RX Data.
if (edge_rx_valid = '1') then
trv_running <= '0';
elsif (edge_tx_valid = '1' and trv_to_restart = '0') then
trv_running <= '1';
trv_to_restart <= '1';
trv_meas_running <= '0';
-- Start measurement on edge on TX Data.
elsif (edge_tx_valid = '1' and trv_meas_to_restart = '0') then
trv_meas_running <= '1';
trv_meas_to_restart <= '1';
end if;
----------------------------------------------------------------
-- Counting
----------------------------------------------------------------
else
trv_meas_to_restart <= '0';
end if;
end if;
end process trv_delay_proc;
----------------------------------------------------------------------------
-- Transceiver delay measurement
----------------------------------------------------------------------------
trv_delay_meas_proc : process(res_n, clk_sys)
begin
if (res_n = ACT_RESET) then
trv_delay <= (OTHERS => '0');
elsif (rising_edge(clk_sys)) then
-- Delay measurement enabled
if (trv_delay_calib = '1') then
-- Restart upon edge on TX Data
if (edge_tx_valid = '1') then
trv_delay <= (OTHERS => '0');
elsif (trv_running = '1') then
-- Increment each clock cycle
elsif (trv_meas_running = '1') then
trv_delay <= std_logic_vector(unsigned(trv_delay) + 1);
else
trv_delay <= trv_delay;
end if;
else
trv_running <= trv_running;
trv_to_restart <= '0';
end if;
end if;
end process trv_delay_proc;
end process;
----------------------------------------------------------------------------
-- Generating shifted sampling signal (sample_sec)
-- Shift register for secondary sampling point. Normal sample point trigger
-- is shifted into shift register to generate delayed sampling point.
----------------------------------------------------------------------------
ssp_shift_reg_comp : shift_reg
generic map(
reset_polarity => ACT_RESET,
reset_value => SSP_SHIFT_RST_VAL,
width => SSP_SHIFT_LENGTH,
shift_down => false
)
port map(
clk => clk_sys,
res_n => res_n,
input => sample_dbt,
preload => ssp_reset,
preload_val => SSP_SHIFT_RST_VAL,
enable => '1',
reg_stat => sample_sec_shift,
output => open
);
----------------------------------------------------------------------------
-- Shift register for TX data. Stored by shift register to be compared
-- with sampled RX Data in Secondary sampling point to detect bit error.
----------------------------------------------------------------------------
tx_data_shift_reg_comp : shift_reg
generic map(
reset_polarity => ACT_RESET,
reset_value => TX_DATA_SHIFT_RST_VAL,
width => TX_DATA_SHIFT_LENGTH,
shift_down => false
)
port map(
clk => clk_sys,
res_n => res_n,
input => data_tx,
preload => ssp_reset,
preload_val => TX_DATA_SHIFT_RST_VAL,
enable => '1',
reg_stat => tx_data_shift,
output => open
);
----------------------------------------------------------------------------
-- Secondary sampling point address decoder. Secondary sampling point
-- is taken from SSP Shift register at position of transceiver delay.
----------------------------------------------------------------------------
sample_sec_comb <= sample_sec_shift(to_integer(unsigned(trv_delay)));
----------------------------------------------------------------------------
-- Delayed TX data address decoder. At the time of secondary sampling point,
-- TX data from TX Data shift register at position of transceiver delay are
-- taken for bit error detection!
----------------------------------------------------------------------------
tx_data_delayed <= tx_data_shift(to_integer(unsigned(trv_delay)));
----------------------------------------------------------------------------
-- Registering secondary sampling point
----------------------------------------------------------------------------
ssp_gen_proc : process(res_n, clk_sys)
begin
if (res_n = '0') then
if (res_n = ACT_RESET) then
sample_sec <= '0';
sample_sec_shift <= (OTHERS => '0');
ssp_shift <= (OTHERS => RECESSIVE);
elsif rising_edge(clk_sys) then
if (ssp_reset = '1') then
-- Erasing secondary sampling signal shift register
sample_sec_shift <= (OTHERS => '0');
-- Erasing Shift register for ssp bit error detection
ssp_shift <= (OTHERS => RECESSIVE);
sample_sec <= '0';
else
-- Shifting DBT sampling signal
sample_sec_shift <= sample_sec_shift(shift_length - 2 downto 0)
& sample_dbt;
-- Shifted signal with trv_delay
sample_sec <= sample_sec_shift(
to_integer(unsigned(trv_delay)));
-- Storing TX data
ssp_shift <= ssp_shift(shift_length - 2 downto 0) &
data_tx;
sample_sec <= sample_sec_comb;
end if;
end if;
end process;
----------------------------------------------------------------------------
-- Delay process for secondary sampling singal
----------------------------------------------------------------------------
......@@ -466,29 +575,89 @@ begin
-- desired then majority out of whole shift register is selected as sampled
-- value!
----------------------------------------------------------------------------
tripple_sam_proc : process(res_n, clk_sys)
trs_shift_reg_comp : shift_reg
generic map(
reset_polarity => ACT_RESET,
reset_value => "000",
width => 3,
shift_down => false
)
port map(
clk => clk_sys,
res_n => res_n,
input => CAN_rx_i,
preload => '0',
preload_val => "000",
enable => '1',
reg_stat => trs_reg,
output => open
);
----------------------------------------------------------------------------
-- Sampling of bus value
----------------------------------------------------------------------------
sample_proc : process(res_n, clk_sys)
begin
if (res_n = ACT_RESET) then
trs_reg <= (OTHERS => RECESSIVE);
prev_Sample <= RECESSIVE;
elsif (rising_edge(clk_sys)) then
-- Shift register realisation
trs_reg(0) <= sync_Data;
trs_reg(2 downto 1) <= trs_reg(1 downto 0);
elsif rising_edge(clk_sys) then
if (drv_ena = ENABLED) then
case sp_control is
----------------------------------------------------------------
-- Sampling with Nominal Bit Time
-- (normal CAN, transceiver, receiver)
--
-- Tripple sampling option selects the majority from last
-- three sampled values
----------------------------------------------------------------
when NOMINAL_SAMPLE =>
if (sample_nbt = '1') then
prev_Sample <= data_rx_nbt;
end if;
----------------------------------------------------------------
-- Sampling with Data Bit Time (CAN FD, reciever).
----------------------------------------------------------------
when DATA_SAMPLE =>
if (sample_dbt = '1') then
prev_Sample <= CAN_rx_i;
end if;
end process;
----------------------------------------------------------------
-- Sampling with Secondary sampling point.
-- (CAN FD, transciever)
----------------------------------------------------------------
when SECONDARY_SAMPLE =>
if (sample_sec = '1') then
prev_Sample <= CAN_rx_i;
end if;
when others =>
prev_Sample <= prev_Sample;
end case;
end if;
end if;
end process sample_proc;
----------------------------------------------------------------------------
-- Sampling of the bus values and bit Error Detection
-- Bit Error detection process
----------------------------------------------------------------------------
sample_proc : process(res_n, clk_sys)
bit_err_detect_proc : process(res_n, clk_sys)
begin
if (res_n = '0') then
prev_Sample <= RECESSIVE;
if (res_n = ACT_RESET) then
bit_Error_reg <= '0';
elsif rising_edge(clk_sys) then
if (drv_ena = ENABLED) then
if (drv_ena = ENABLED and bit_err_enable = '1') then
case sp_control is
----------------------------------------------------------------
......@@ -498,34 +667,13 @@ begin
when NOMINAL_SAMPLE =>
if (sample_nbt = '1') then
-- Tripple sampling option selects the majority from last
-- three sampled values
if (drv_sam = '1') then
prev_Sample <= trs_majority;
-- Bit Error detection
if (trs_majority = data_tx) or
(bit_err_enable = '0')
then
-- If TX data are equal to RX Data -> No problem.
if (data_rx_nbt = data_tx) then
bit_Error_reg <= '0';
else
bit_Error_reg <= '1';
end if;
else
prev_Sample <= sync_Data;
-- Bit Error detection when sampling
if (sync_Data = data_tx) or
(bit_err_enable = '0')
then
bit_Error_reg <= '0';
else
bit_Error_reg <= '1';
end if;
end if;
else
prev_Sample <= prev_Sample;
bit_Error_reg <= bit_Error_reg;
end if;
----------------------------------------------------------------
......@@ -533,16 +681,13 @@ begin
----------------------------------------------------------------
when DATA_SAMPLE =>
if (sample_dbt = '1') then
prev_Sample <= sync_Data;
--Bit Error detection when sampling
if (sync_Data = data_tx) or (bit_err_enable = '0') then
if (CAN_rx_i = data_tx) then
bit_Error_reg <= '0';
else
bit_Error_reg <= '1';
end if;
else
bit_Error_reg <= bit_Error_reg;
prev_Sample <= prev_Sample;
end if;
----------------------------------------------------------------
......@@ -551,35 +696,46 @@ begin
----------------------------------------------------------------
when SECONDARY_SAMPLE =>
if (sample_sec = '1') then
prev_Sample<=sync_Data;
-- Bit Error comparison differs in this case, not actual
-- transmitted bit is compared, but delayed bit is
-- compared (in ssp_shift register)