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phy: rx: Implement error handling for Manchester

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This commit is contained in:
Markus Koch 2021-08-28 14:23:15 +02:00
parent 5d6df0219b
commit 1f894866ab
1 changed files with 14 additions and 5 deletions
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17
trashernet/trashernet_phy.vhd
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@ -98,7 +98,7 @@ begin
signal bit_ev : bit_ev_t; signal bit_ev : bit_ev_t;
-- Bit recovery -- Bit recovery
type demanchestization_state_t is (SYNC, DATA); type demanchestization_state_t is (SYNC, DATA, ERROR);
signal demanchestization_state : demanchestization_state_t; signal demanchestization_state : demanchestization_state_t;
begin begin
-- Detects spacing of transitions -- Detects spacing of transitions
@ -170,23 +170,32 @@ begin
demanchestization_state <= SYNC; demanchestization_state <= SYNC;
bit_stb <= '0'; bit_stb <= '0';
rx_active <= '0'; rx_active <= '0';
rx_error <= '0';
elsif rising_edge(clk) then elsif rising_edge(clk) then
bit_stb <= '0'; bit_stb <= '0';
rx_error <= '0';
if (bit_ev /= NONE) then if (bit_ev /= NONE) then
rx_active <= '1';
case demanchestization_state is case demanchestization_state is
when SYNC => when SYNC =>
if (bit_ev = KEEP) then if (bit_ev = KEEP) then
bit_value <= '1'; bit_value <= '1';
demanchestization_state <= DATA; demanchestization_state <= DATA;
rx_active <= '1';
end if; end if;
when DATA => when DATA => -- @suppress: Condition outside of case allows to exit this state
bit_value <= not bit_value when bit_ev = TOGGLE else bit_value; bit_value <= not bit_value when bit_ev = TOGGLE else bit_value;
bit_stb <= '1'; bit_stb <= '1';
when ERROR => -- @suppress: Condition outside of case allows to exit this state
null;
end case; end case;
end if; end if;
if (bit_ev = ERROR) then
rx_error <= '1';
demanchestization_state <= ERROR;
end if;
if (not transition_activity) then if (not transition_activity) then
demanchestization_state <= SYNC; demanchestization_state <= SYNC;
rx_active <= '0'; rx_active <= '0';