2 use ieee.std_logic_1164.all;
3 use ieee.std_logic_unsigned.all;
4 use ieee.numeric_std.all;
6 use work.lx_rocon_pkg.all;
8 -- LX Master (Transmitter)
9 entity lxmaster_transmitter is
13 reset_i : in std_logic;
15 clock_o : out std_logic;
16 mosi_o : out std_logic;
17 sync_o : out std_logic;
19 register_i : in std_logic;
20 register_o : out std_logic;
21 register_we_i : in std_logic;
23 mem_clk_i : in std_logic;
24 mem_en_i : in std_logic;
25 mem_we_i : in std_logic_vector(1 downto 0);
26 mem_addr_i : in std_logic_vector(8 downto 0);
27 mem_data_i : in std_logic_vector(15 downto 0);
28 mem_data_o : out std_logic_vector(15 downto 0)
30 end lxmaster_transmitter;
32 architecture Behavioral of lxmaster_transmitter is
35 type state_t is (ST_INIT, ST_READY, ST_XFER, ST_CRC, ST_END);
36 constant frame_length_c : positive := 2500; -- 50 MHz -> 20 kHz
37 constant msg_max_count_c : positive := 8;
38 -- RAM Access (both ARM and Tumbl)
39 signal ram_en_s : std_logic;
40 signal ram_rst_s : std_logic;
42 signal ram_addr_s : std_logic_vector(8 downto 0);
43 signal ram_addr_r : std_logic_vector(8 downto 0);
44 signal ram_data_o_s : std_logic_vector(15 downto 0);
46 signal lxmaster_state_s : state_t;
47 signal lxmaster_state_r : state_t;
48 signal lxmaster_last_word_s : std_logic;
49 signal lxmaster_last_word_r : std_logic;
51 signal lxmaster_num_data_s : std_logic_vector(7 downto 0); -- If 0 then the peripheral is not active this cycle
52 signal lxmaster_num_data_r : std_logic_vector(7 downto 0);
53 signal lxmaster_loaded_data_s : std_logic_vector(15 downto 0);
54 signal lxmaster_loaded_data_r : std_logic_vector(15 downto 0);
55 signal lxmaster_data_counter_s : std_logic_vector(3 downto 0); -- Shift: 0 - 15
56 signal lxmaster_data_counter_r : std_logic_vector(3 downto 0);
58 signal lxmaster_sync_s : std_logic;
59 signal lxmaster_sync_r : std_logic;
60 signal lxmaster_sync_last_bit_s : std_logic;
61 signal lxmaster_sync_last_bit_r : std_logic;
63 signal lxmaster_frame_counter_s : natural range 0 to (frame_length_c-1);
64 signal lxmaster_msg_counter_s : natural range 0 to (msg_max_count_c-1);
65 signal lxmaster_msg_counter_r : natural range 0 to (msg_max_count_c-1);
67 signal lxmaster_crc_data_s : std_logic;
68 signal lxmaster_crc_reset_s : std_logic;
69 signal lxmaster_crc_out_s : std_logic_vector(7 downto 0);
70 signal lxmaster_crc_reg_s : std_logic_vector(7 downto 0);
71 signal lxmaster_crc_reg_r : std_logic_vector(7 downto 0);
73 signal lxmaster_ram_reset_s : std_logic;
75 -- Bit 0: Transmitter - use first or second buffer
76 signal lxmaster_register_in_s : std_logic;
77 signal lxmaster_register_out_s : std_logic;
81 -- Directly route out some signals
82 clock_o <= clk_i; -- Cannot mix with logic
83 sync_o <= not lxmaster_sync_r; -- Active in log. 0
84 mosi_o <= '1' when lxmaster_sync_r = '0' and lxmaster_sync_last_bit_r = '0'
85 else lxmaster_crc_reg_r(0) when lxmaster_state_r = ST_CRC
86 else lxmaster_loaded_data_r(0);
88 lxmaster_crc_reg_s <= '0' & lxmaster_crc_reg_r(7 downto 1) when lxmaster_state_r = ST_CRC else lxmaster_crc_out_s;
89 lxmaster_crc_data_s <= '1' when lxmaster_state_r = ST_CRC else lxmaster_loaded_data_r(0);
90 lxmaster_crc_reset_s <= '1' when lxmaster_state_r /= ST_XFER or reset_i = '1' else '0';
93 register_o <= lxmaster_register_out_s;
95 ram: xilinx_dualport_bram_write_first
108 wea => (others => '0'),
110 dina => (others => '0'),
111 douta => ram_data_o_s,
126 reset_i => lxmaster_crc_reset_s,
127 input_i => lxmaster_crc_data_s,
128 crc_o => lxmaster_crc_out_s
131 ram_rst_s <= reset_i or lxmaster_ram_reset_s;
134 -- TODO: Maybe some exception handling (overflows etc.)
136 process (ram_data_o_s, ram_addr_r, lxmaster_state_r, lxmaster_loaded_data_r, lxmaster_num_data_r, lxmaster_msg_counter_r,
137 lxmaster_last_word_r, lxmaster_data_counter_r, reset_i, lxmaster_frame_counter_s, lxmaster_register_in_s)
138 variable ram_addr_v : std_logic_vector(8 downto 0);
142 lxmaster_ram_reset_s <= '0';
143 lxmaster_sync_last_bit_s <= '0';
144 -- Defaults of state variables (no change)
145 ram_addr_s <= ram_addr_r;
146 lxmaster_state_s <= lxmaster_state_r;
147 lxmaster_loaded_data_s <= lxmaster_loaded_data_r;
148 lxmaster_data_counter_s <= lxmaster_data_counter_r;
149 lxmaster_num_data_s <= lxmaster_num_data_r;
150 lxmaster_msg_counter_s <= lxmaster_msg_counter_r;
151 lxmaster_last_word_s <= lxmaster_last_word_r;
153 if reset_i = '1' then
154 lxmaster_num_data_s <= x"00";
155 lxmaster_loaded_data_s <= x"0000";
156 lxmaster_state_s <= ST_END;
157 lxmaster_sync_s <= '0';
158 lxmaster_last_word_s <= '0';
160 ram_addr_s <= '0' & x"00";
163 lxmaster_ram_reset_s <= '1';
167 -- OK, we are enabled, default values
168 lxmaster_sync_s <= '0'; -- Not transferring
169 ram_en_s <= '0'; -- Not reading
171 case lxmaster_state_r is
174 -- We just read number of commands
175 if ram_data_o_s(7 downto 0) = x"00" then
176 lxmaster_state_s <= ST_END; --Nothing
178 lxmaster_state_s <= ST_READY; -- Make next read init the transfer
181 -- Prepare message counter
182 lxmaster_msg_counter_s <= 0;
184 -- Regardless, write the number of data and schedule reading
185 ram_addr_v := ram_addr_r(8) & ram_data_o_s(15 downto 8); -- Update address
186 ram_addr_s <= ram_addr_v;
187 lxmaster_num_data_s <= std_logic_vector(unsigned(ram_addr_v(7 downto 0)) + unsigned(ram_data_o_s(7 downto 0)));
188 ram_en_s <= '1'; -- Read
191 -- We are ready to begin transferring
192 lxmaster_loaded_data_s <= ram_data_o_s;
193 lxmaster_sync_s <= '1'; -- Transferring data next cycle
194 lxmaster_data_counter_s <= x"0"; -- Reset counter
195 lxmaster_state_s <= ST_XFER; --Go to transfer loop
198 lxmaster_loaded_data_s <= '0' & lxmaster_loaded_data_r(15 downto 1); -- Shift it
199 lxmaster_sync_s <= '1'; -- Transferring data next cycle
201 if lxmaster_data_counter_r = x"E" then
202 lxmaster_data_counter_s <= lxmaster_data_counter_r + 1; -- Increment
204 if (ram_addr_r(7 downto 0) + 1) /= lxmaster_num_data_r then
205 -- At 14th bit, we need to read from RAM if more words are to come
206 ram_addr_s <= ram_addr_r(8) & (ram_addr_r(7 downto 0) + 1); -- Update address
207 ram_en_s <= '1'; -- Read
208 lxmaster_last_word_s <= '0';
210 lxmaster_last_word_s <= '1';
213 elsif lxmaster_data_counter_r = x"F" then
214 -- At 15th bit, we either stop if ram_addr_r equals lxmaster_num_data_r
215 if lxmaster_last_word_r = '1' then
216 lxmaster_state_s <= ST_CRC;
217 lxmaster_data_counter_s <= x"0";
219 lxmaster_loaded_data_s <= ram_data_o_s;
220 lxmaster_data_counter_s <= x"0";
224 lxmaster_data_counter_s <= lxmaster_data_counter_r + 1;
229 -- Check if this is last command, first read one more
230 if lxmaster_data_counter_r = x"0" then
231 if lxmaster_msg_counter_r = (msg_max_count_c - 1) then
232 lxmaster_ram_reset_s <= '1'; -- Make sure we read 0 if we are on the last message
234 lxmaster_msg_counter_s <= lxmaster_msg_counter_r + 1;
237 ram_addr_s <= ram_addr_r(8) & std_logic_vector(to_unsigned(lxmaster_msg_counter_r + 1, ram_addr_r'length - 1)); -- Update address
238 ram_en_s <= '1'; -- Read
240 elsif lxmaster_data_counter_r = x"1" then
242 if ram_data_o_s(15 downto 8) >= msg_max_count_c then -- Need to read first command, make sure it's valid
243 ram_addr_v := ram_addr_r(8) & ram_data_o_s(15 downto 8); -- Update address
244 ram_addr_s <= ram_addr_v;
245 lxmaster_num_data_s <= std_logic_vector(unsigned(ram_addr_v(7 downto 0)) + unsigned(ram_data_o_s(7 downto 0)));
246 ram_en_s <= '1'; -- Read
248 lxmaster_num_data_s <= x"00"; -- Signalize termination
253 if lxmaster_data_counter_r = x"7" then -- Ending
254 lxmaster_data_counter_s <= x"0";
256 if lxmaster_num_data_r(7 downto 0) = x"00" then
257 lxmaster_state_s <= ST_END; -- Last command
259 -- Begin transmission of next data
260 lxmaster_loaded_data_s <= ram_data_o_s;
261 lxmaster_sync_s <= '1'; -- Transferring data next cycle
262 lxmaster_data_counter_s <= x"0"; -- Reset counter
263 lxmaster_state_s <= ST_XFER; --Go to transfer loop
267 if lxmaster_data_counter_r /= x"6" then
268 lxmaster_sync_s <= '1'; -- Sync goes inactive to signalize termination
270 lxmaster_sync_last_bit_s <= '1';
273 lxmaster_data_counter_s <= lxmaster_data_counter_r + 1; -- Increment
277 if lxmaster_frame_counter_s = (frame_length_c - 1) then
278 -- Initialize first step
279 lxmaster_state_s <= ST_INIT;
280 ram_addr_s <= lxmaster_register_in_s & x"00";
290 -- This function toggles outputs directly, make sure the outputs
291 -- are updated with clock to minimize phase.
296 wait until clk_i'event and clk_i = '1';
299 ram_addr_r <= ram_addr_s;
300 lxmaster_state_r <= lxmaster_state_s;
301 lxmaster_loaded_data_r <= lxmaster_loaded_data_s;
302 lxmaster_data_counter_r <= lxmaster_data_counter_s;
303 lxmaster_num_data_r <= lxmaster_num_data_s;
304 lxmaster_crc_reg_r <= lxmaster_crc_reg_s;
305 lxmaster_msg_counter_r <= lxmaster_msg_counter_s;
306 lxmaster_last_word_r <= lxmaster_last_word_s;
309 if reset_i = '1' then
310 lxmaster_frame_counter_s <= (frame_length_c - 1);
311 lxmaster_register_in_s <= '0';
312 lxmaster_register_out_s <= '0';
315 if register_we_i = '1' then
316 lxmaster_register_in_s <= register_i;
319 if lxmaster_frame_counter_s = (frame_length_c - 1) then
320 lxmaster_register_out_s <= lxmaster_register_in_s;
321 lxmaster_frame_counter_s <= 0;
323 lxmaster_frame_counter_s <= lxmaster_frame_counter_s + 1;
328 lxmaster_sync_r <= lxmaster_sync_s;
329 lxmaster_sync_last_bit_r <= lxmaster_sync_last_bit_s;