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1 -- $Id: ser_par_con.vhd,v 1.1 2007-03-11 08:55:29 sithglan Exp $
2
3 library ieee;
4 use ieee.std_logic_1164.all;
5 use ieee.std_logic_unsigned.all;
6
7 entity SER_PAR_CON is
8 port
9 (
10 PCI_CLOCK :in std_logic;
11 RESET :in std_logic;
12 SPC_ENABLE :in std_logic; -- Driver Enable Sender/Receiver
13 SYNC_R_FIFO_FFn :in std_logic; -- FIFO Full Flag (low active)
14 SERIAL_IN :in std_logic; -- Serial Input
15 R_FIFO_WRITEn :out std_logic; -- FIFO Write (low active)
16 SPC_RDY_OUT :out std_logic; -- Ready to Receive Data
17 PAR_OUT :out std_logic_vector(7 downto 0)
18 );
19 end entity SER_PAR_CON;
20
21
22 architecture SER_PAR_CON_DESIGN of SER_PAR_CON is
23
24 -- constant STATE_RECV :std_logic_vector(3 downto 0) := "0001";
25 constant STATE_RECV_START_BIT :std_logic_vector(3 downto 0) := "0010";
26 constant STATE_RECV_BIT_0 :std_logic_vector(3 downto 0) := "0011";
27 constant STATE_RECV_BIT_1 :std_logic_vector(3 downto 0) := "0100";
28 constant STATE_RECV_BIT_2 :std_logic_vector(3 downto 0) := "0101";
29 constant STATE_RECV_BIT_3 :std_logic_vector(3 downto 0) := "0110";
30 constant STATE_RECV_BIT_4 :std_logic_vector(3 downto 0) := "0111";
31 constant STATE_RECV_BIT_5 :std_logic_vector(3 downto 0) := "1000";
32 constant STATE_RECV_BIT_6 :std_logic_vector(3 downto 0) := "1001";
33 constant STATE_RECV_BIT_7 :std_logic_vector(3 downto 0) := "1010";
34 constant STATE_RECV_FIFOFULL :std_logic_vector(3 downto 0) := "1011";
35
36 signal COUNT :std_logic_vector (3 downto 0);
37 signal STATE :std_logic_vector (3 downto 0);
38 signal STARTBIT :std_logic_vector (3 downto 0);
39
40
41 attribute syn_state_machine:boolean;
42 attribute syn_state_machine of STATE: signal is false;
43 attribute syn_state_machine of COUNT: signal is false;
44
45 begin
46
47 process(PCI_CLOCK)
48 begin
49 if (PCI_CLOCK'event and PCI_CLOCK = '1') then
50 if ("0000" < COUNT) then
51 COUNT <= COUNT - 1;
52 end if;
53
54 -- war nicht das Problem des Datenverlusts
55 -- if (R_FIFO_WRITEn = '0' and COUNT = "0000") then
56 -- R_FIFO_WRITEn <= '1';
57 --- end if;
58
59 if (RESET = '1') then
60 STATE <= STATE_RECV_START_BIT;
61 COUNT <= "0000";
62 R_FIFO_WRITEn <= '1';
63
64 elsif (SPC_ENABLE = '1') then
65
66 if (STATE = STATE_RECV_START_BIT) then
67 R_FIFO_WRITEn <= '1';
68 if (STARTBIT = "0011") then
69 COUNT <= "0011";
70 STATE <= STATE_RECV_BIT_0;
71 end if;
72
73 elsif (STATE = STATE_RECV_FIFOFULL) then
74 if (SYNC_R_FIFO_FFn = '1') then
75 R_FIFO_WRITEn <= '0';
76 STATE <= STATE_RECV_START_BIT;
77 end if;
78
79 elsif (COUNT = "0000") then
80 COUNT <= "0011";
81 case STATE is
82
83 when STATE_RECV_BIT_0 =>
84 PAR_OUT(0) <= STARTBIT(0);
85 STATE <= STATE_RECV_BIT_1;
86
87 when STATE_RECV_BIT_1 =>
88 PAR_OUT(1) <= STARTBIT(0);
89 STATE <= STATE_RECV_BIT_2;
90
91 when STATE_RECV_BIT_2 =>
92 PAR_OUT(2) <= STARTBIT(0);
93 STATE <= STATE_RECV_BIT_3;
94
95 when STATE_RECV_BIT_3 =>
96 PAR_OUT(3) <= STARTBIT(0);
97 STATE <= STATE_RECV_BIT_4;
98
99 when STATE_RECV_BIT_4 =>
100 PAR_OUT(4) <= STARTBIT(0);
101 STATE <= STATE_RECV_BIT_5;
102
103 when STATE_RECV_BIT_5 =>
104 PAR_OUT(5) <= STARTBIT(0);
105 STATE <= STATE_RECV_BIT_6;
106
107 when STATE_RECV_BIT_6 =>
108 PAR_OUT(6) <= STARTBIT(0);
109 STATE <= STATE_RECV_BIT_7;
110
111 when STATE_RECV_BIT_7 =>
112 PAR_OUT(7) <= STARTBIT(0);
113
114 if (SYNC_R_FIFO_FFn = '1') then
115 STATE <= STATE_RECV_START_BIT;
116 R_FIFO_WRITEn <= '0';
117 else
118 STATE <= STATE_RECV_FIFOFULL;
119 end if;
120
121 when others =>
122 STATE <= STATE_RECV_START_BIT;
123
124 end case;
125 end if; -- COUNT
126 end if; -- RESET ... / SPC_ENABLE ...
127 end if; -- PCI_CLOCK ...
128 end process;
129
130 process(PCI_CLOCK)
131 begin
132 if (PCI_CLOCK'event and PCI_CLOCK = '1') then
133 SPC_RDY_OUT <= SPC_ENABLE AND SYNC_R_FIFO_FFn;
134 end if;
135 end process;
136
137
138 process(PCI_CLOCK)
139 begin
140 if (PCI_CLOCK'event and PCI_CLOCK = '1') then
141 if (RESET = '1') then
142 STARTBIT <= "0000";
143 else
144 STARTBIT(0) <= SERIAL_IN;
145 STARTBIT(1) <= STARTBIT(0);
146 STARTBIT(2) <= STARTBIT(1);
147 STARTBIT(3) <= STARTBIT(2);
148 end if;
149 end if;
150 end process;
151
152 end architecture SER_PAR_CON_DESIGN;
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