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CTU CAN FD IP Core
Commit 5dd2be29 authored by Ille, Ondrej, Ing.'s avatar Ille, Ondrej, Ing.
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Some additional comments in Core top.

parent 5385fe64
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Showing with 52 additions and 36 deletions
src/CAN_Core/core_top.vhd
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......@@ -881,39 +881,53 @@ begin
dst_ctr => dst_ctr
);
-- Temporary different data source of crc for transciever FD!!!
-- CRC calculated from transcieved data!!
----------------------------------------------------------------------------
-- CRC From RX Data can't be always calculated from RX Data! In case of
-- secondary sampling, bit length might be shorter than Propagation from TX
-- to RX over transceiver! Thus in case of secondary sampling, even CRC
-- from RX data is calculated from TX Data!
----------------------------------------------------------------------------
data_crc_wbs <= data_tx_int when sp_control_int = SECONDARY_SAMPLE else
data_rx_int;
data_crc_nbs <= data_tx_before_stuff when sp_control_int = SECONDARY_SAMPLE
else
data_destuffed ;
data_destuffed;
----------------------------------------------------------------------------
-- Driving bus aliases
----------------------------------------------------------------------------
drv_set_ctr_val <= drv_bus(DRV_SET_CTR_VAL_HIGH downto
DRV_SET_CTR_VAL_LOW);
DRV_SET_CTR_VAL_LOW);
drv_set_rx_ctr <= drv_bus(DRV_SET_RX_CTR_INDEX);
drv_set_tx_ctr <= drv_bus(DRV_SET_TX_CTR_INDEX);
drv_int_loopback_ena <= drv_bus(DRV_INT_LOOBACK_ENA_INDEX);
----------------------------------------------------------------------------
-- Output propagation
----------------------------------------------------------------------------
arbitration_lost_out <= arbitration_lost;
tx_finished <= tran_valid;
sof_pulse <= sof_pulse_r;
bus_off_start <= bus_off_start_int;
br_shifted <= br_shifted_int;
ssp_reset <= ssp_reset_int;
trv_delay_calib <= trv_delay_calib_int;
---------------------
--CRC Multiplexing --
---------------------
----------------------------------------------------------------------------
-- CRC Multiplexors.
--
-- CRC data sources like so:
-- 1. Transceiver, CAN FD Frame -> TX Data after bit stuffing.
-- 2. Transceiver, CAN 2.0 Frame -> TX Data before bit stuffing.
-- 3. Receiver, CAN FD Frame -> RX Data before bit destuffing.
-- 4. Receiver, CAN 2.0 Frame -> RX Data after bit destuffing.
----------------------------------------------------------------------------
crc15 <= crc15_wbs_tx when (OP_State = transciever and
tran_frame_type = FD_CAN) else
......@@ -958,7 +972,7 @@ begin
----------------------------------------------------------------------------
-- Multiplexing of stuff counter and destuff counter
-- Multiplexing of stuff counter and destuff counter
----------------------------------------------------------------------------
st_ctr_resolved <= dst_ctr when (OP_State = reciever) else
bst_ctr when (OP_State = transciever) else
......@@ -966,7 +980,7 @@ begin
----------------------------------------------------------------------------
-- Trigger signals multiplexing
-- Trigger signals registering. Creating delayed signals
----------------------------------------------------------------------------
trig_cr : process(clk_sys, res_n)
begin
......@@ -974,15 +988,22 @@ begin
sync_dbt_del_2 <= '0';
sync_nbt_del_2 <= '0';
tran_trig_del_1 <= '0';
bds_trig_del_1 <= '0';
elsif rising_edge(clk_sys) then
sync_dbt_del_2 <= sync_dbt_del_1;
sync_nbt_del_2 <= sync_nbt_del_1;
tran_trig_del_1 <= tran_trig;
bds_trig_del_1 <= bds_trig;
end if;
end process;
-- Note: when secondary sampling point is used transcieve signals
-- remains the same
----------------------------------------------------------------------------
-- Multiplexors for TX/RX Triggers. These Triggers are used to
-- transmitt/receive data from/to Protocol Control.
-- Note that Secondary sampling point is used only by Bus sync for bit
-- error detection!
----------------------------------------------------------------------------
tran_trig <= sync_nbt and (not data_halt)
when (sp_control_int = NOMINAL_SAMPLE) else
......@@ -1004,13 +1025,14 @@ begin
when (sp_control_int = SECONDARY_SAMPLE) else
'0';
----------------------------------------------------------------------------
--Note: Due to not functioning Secondary sample point normal data phasee
-- sample point used!!! Secondary sample point used only for bit error
-- detection during Data Phase!!!
-- Multiplexors for Bit Stuffing/Destuffing triggers. These are used to
-- process data by Bit Stuffing/Destuffing circuits.
-- Note that Secondary sampling point is used only by Bus sync for bit
-- error detection!
----------------------------------------------------------------------------
bs_trig <= sync_nbt_del_1 when (sp_control_int = NOMINAL_SAMPLE) else
sync_dbt_del_1 when (sp_control_int = DATA_SAMPLE) else
sync_dbt_del_1 when (sp_control_int = SECONDARY_SAMPLE) else
......@@ -1021,6 +1043,7 @@ begin
sync_dbt_del_1 when (sp_control_int = SECONDARY_SAMPLE) else
'0';
----------------------------------------------------------------------------
-- According to CAN FD specification fixed stuff bits are never included in
-- CRC calculation. With NON ISO there is no problem. CRC calculation in the
......@@ -1040,16 +1063,6 @@ begin
else
bds_trig_del_1;
bds_del_proc : process(clk_sys, res_n)
begin
if (res_n = ACT_RESET) then
bds_trig_del_1 <= '0';
elsif rising_edge(clk_sys) then
bds_trig_del_1 <= bds_trig;
end if;
end process;
crc_nbs_trig <= (sync_dbt and (not data_halt))
when (sp_control_int = SECONDARY_SAMPLE)
......@@ -1065,6 +1078,7 @@ begin
error_passive_changed <= error_passive_changed_int;
error_warning_limit <= error_warning_limit_int;
----------------------------------------------------------------------------
-- Data Received by Protocol control are from Bit Destuffing, apart from
-- following cases:
......@@ -1095,7 +1109,8 @@ begin
drv_int_loopback_ena = '1')
else
data_tx_from_PC;
----------------------------------------------------------------------------
-- Bus traffic measurement
----------------------------------------------------------------------------
......@@ -1122,7 +1137,8 @@ begin
end if;
end process;
----------------------------------------------------------------------------
-- STATUS Bus Implementation
----------------------------------------------------------------------------
......
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