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[/] [sd_mmc_emulator/] [trunk/] [rtl/] [fifo_pack.vhd] - Blame information for rev 2

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1 2 jclaytons 
library ieee;
2 
use ieee.std_logic_1164.all;
3 
use ieee.numeric_std.all;
4 
 
5 
package fifo_pack is
6 
 
7 
  component generic_fifo
8 
    generic(
9 
      WIDTH          : integer;
10 
      DEPTH          : integer;
11 
      PF_FULL_POINT  : integer;
12 
      PF_FLAG_POINT  : integer;
13 
      PF_EMPTY_POINT : integer
14 
    );
15 
    port (
16 
      sys_rst_n     : in  std_logic; -- Asynchronous
17 
      sys_clk       : in  std_logic;
18 
      sys_clk_en    : in  std_logic;
19 
 
20 
      reset_i       : in std_logic;  -- Synchronous
21 
 
22 
      fifo_rd_i     : in  std_logic;
23 
      fifo_dout     : out unsigned(WIDTH-1 downto 0);
24 
 
25 
      fifo_wr_i     : in  std_logic;
26 
      fifo_din      : in  unsigned(WIDTH-1 downto 0);
27 
 
28 
      fifo_full     : out std_logic;
29 
      fifo_empty    : out std_logic;
30 
      fifo_pf_full  : out std_logic;
31 
      fifo_pf_flag  : out std_logic;
32 
      fifo_pf_empty : out std_logic
33 
    );
34 
  end component;
35 
 
36 
  component fifo_with_fill_level
37 
    generic(
38 
      WIDTH            : integer;
39 
      DEPTH            : integer;
40 
      FILL_LEVEL_BITS  : integer; -- Should be at least int(floor(log2(DEPTH))+1.0)
41 
      PF_FULL_POINT    : integer;
42 
      PF_FLAG_POINT    : integer;
43 
      PF_EMPTY_POINT   : integer
44 
    );
45 
    port (
46 
      sys_rst_n       : in  std_logic; -- Asynchronous
47 
      sys_clk         : in  std_logic;
48 
      sys_clk_en      : in std_logic;
49 
 
50 
      reset_i         : in std_logic;  -- Synchronous
51 
 
52 
      fifo_rd_i       : in  std_logic;
53 
      fifo_dout       : out unsigned(WIDTH-1 downto 0);
54 
 
55 
      fifo_wr_i       : in  std_logic;
56 
      fifo_din        : in  unsigned(WIDTH-1 downto 0);
57 
 
58 
      fifo_fill_level : out unsigned(FILL_LEVEL_BITS-1 downto 0);
59 
      fifo_full       : out std_logic;
60 
      fifo_empty      : out std_logic;
61 
      fifo_pf_full    : out std_logic;
62 
      fifo_pf_flag    : out std_logic;
63 
      fifo_pf_empty   : out std_logic
64 
    );
65 
  end component;
66 
 
67 
  component swiss_army_fifo
68 
    generic(
69 
      USE_BRAM         : integer; -- Set to nonzero value for BRAM, zero for distributed RAM
70 
      WIDTH            : integer;
71 
      DEPTH            : integer;
72 
      FILL_LEVEL_BITS  : integer; -- Should be at least int(floor(log2(DEPTH))+1.0)
73 
      PF_FULL_POINT    : integer;
74 
      PF_FLAG_POINT    : integer;
75 
      PF_EMPTY_POINT   : integer
76 
    );
77 
    port (
78 
      sys_rst_n       : in  std_logic; -- Asynchronous
79 
      sys_clk         : in  std_logic;
80 
      sys_clk_en      : in  std_logic;
81 
 
82 
      reset_i         : in std_logic;  -- Synchronous
83 
 
84 
      fifo_wr_i       : in  std_logic;
85 
      fifo_din        : in  unsigned(WIDTH-1 downto 0);
86 
 
87 
      fifo_rd_i       : in  std_logic;
88 
      fifo_dout       : out unsigned(WIDTH-1 downto 0);
89 
 
90 
      fifo_fill_level : out unsigned(FILL_LEVEL_BITS-1 downto 0);
91 
      fifo_full       : out std_logic;
92 
      fifo_empty      : out std_logic;
93 
      fifo_pf_full    : out std_logic;
94 
      fifo_pf_flag    : out std_logic;
95 
      fifo_pf_empty   : out std_logic
96 
    );
97 
  end component;
98 
 
99 
  component swiss_army_fifo_cdc
100 
    generic (
101 
      USE_BRAM         : integer; -- Set to nonzero value for BRAM, zero for distributed RAM
102 
      WIDTH            : integer;
103 
      DEPTH            : integer;
104 
      FILL_LEVEL_BITS  : integer; -- Should be at least int(floor(log2(DEPTH))+1.0)
105 
      PF_FULL_POINT    : integer;
106 
      PF_FLAG_POINT    : integer;
107 
      PF_EMPTY_POINT   : integer
108 
    );
109 
    port (
110 
      sys_rst_n        : in  std_logic; -- Asynchronous
111 
 
112 
      wr_clk_i         : in  std_logic;
113 
      wr_clk_en_i      : in  std_logic;
114 
      wr_reset_i       : in  std_logic;  -- Synchronous
115 
      wr_en_i          : in  std_logic;
116 
      wr_dat_i         : in  unsigned(WIDTH-1 downto 0);
117 
      wr_fifo_level    : out unsigned(FILL_LEVEL_BITS-1 downto 0);
118 
      wr_fifo_full     : out std_logic;
119 
      wr_fifo_empty    : out std_logic;
120 
      wr_fifo_pf_full  : out std_logic;
121 
      wr_fifo_pf_flag  : out std_logic;
122 
      wr_fifo_pf_empty : out std_logic;
123 
 
124 
      rd_clk_i         : in  std_logic;
125 
      rd_clk_en_i      : in  std_logic;
126 
      rd_reset_i       : in  std_logic;  -- Synchronous
127 
      rd_en_i          : in  std_logic;
128 
      rd_dat_o         : out unsigned(WIDTH-1 downto 0);
129 
      rd_fifo_level    : out unsigned(FILL_LEVEL_BITS-1 downto 0);
130 
      rd_fifo_full     : out std_logic;
131 
      rd_fifo_empty    : out std_logic;
132 
      rd_fifo_pf_full  : out std_logic;
133 
      rd_fifo_pf_flag  : out std_logic;
134 
      rd_fifo_pf_empty : out std_logic
135 
    );
136 
  end component;
137 
 
138 
  component data_packer
139 
    generic (
140 
      ADR_W          : integer; -- Bit width of snoop address
141 
      DATA_IN_W      : integer; -- Maximum in_dat_i word size
142 
      LOG2_DATA_IN_W : integer; -- Bit width of in_word_size_i
143 
      DATA_OUT_W     : integer; -- Bit width of archive data
144 
      FIFO_DEPTH     : integer  -- Size of BRAM FIFO buffer
145 
    );
146 
    port (
147 
 
148 
      sys_rst_n  : in std_logic;
149 
      sys_clk    : in std_logic;
150 
      sys_clk_en : in std_logic;
151 
 
152 
      -- Input Port
153 
      in_dat_i        : in  unsigned(DATA_IN_W-1 downto 0);
154 
      in_word_size_i  : in  unsigned(LOG2_DATA_IN_W downto 0);
155 
      in_last_word_i  : in  std_logic;
156 
      in_adr_i        : in  unsigned(ADR_W-1 downto 0);
157 
      in_match_adr_i  : in  unsigned(ADR_W-1 downto 0);
158 
      in_cyc_i        : in  std_logic;
159 
      in_ack_i        : in  std_logic;
160 
 
161 
      -- Status
162 
      fifo_full_o     : out std_logic;
163 
      fifo_reset_i    : in  std_logic;
164 
 
165 
      -- Output Port
166 
      tx_done_i       : in  std_logic;
167 
      tx_buff_i       : in  unsigned(ADR_W-1 downto 0);
168 
      out_dat_o       : out unsigned(DATA_OUT_W-1 downto 0);
169 
      out_last_word_o : out std_logic;
170 
      out_cyc_o       : out std_logic;
171 
      out_ack_i       : in  std_logic
172 
 
173 
    );
174 
  end component;
175 
 
176 
end fifo_pack;
177 
 
178 
 
179 
--------------------------------------------------------------
180 
-- Generic FIFO
181 
--------------------------------------------------------------
182 
-- Description:
183 
--
184 
-- This is a generic, parameterized FIFO module meant to be used
185 
-- by logic which is already synchronous to the system clock.
186 
-- The input and output use a single system clock.
187 
-- Also, there is no handshaking for read/write requests.
188 
-- This means that Read/Write request assertions must conform to
189 
-- setup & hold times within the system clock domain in order for
190 
-- this FIFO to operate correctly.  In other words, don't use
191 
-- this FIFO with any inputs originating from a different clock
192 
-- domain.
193 
--
194 
-- This FIFO has a memory array which is not address pipelined,
195 
-- and which operates in a "single clock cycle response" mode
196 
-- so that writes and reads are completed at the first clock
197 
-- edge following the assertion of a read or write request.
198 
-- Therefore, the system clock speed must be limited to speeds
199 
-- at which the memory can respond in that fashion.  Also, it is
200 
-- assumed that the memory array used for the FIFO storage will
201 
-- be synthesized with separate input and output data paths, such
202 
-- that reads and writes can occur at the same clock edge.  Thus
203 
-- there does not need to be a prioritization of read vs. write
204 
-- operations, since they can both occur at any given clock edge.
205 
--
206 
-- NOTES:
207 
-- The DEPTH does not need to be a power of two.
208 
-- This FIFO has been simulated using DEPTH values down to as
209 
-- low as 2.  Depths less than this are considered degenerate
210 
-- cases, and will produce errors.
211 
--
212 
-- Since the read_row points to the data about to be read,
213 
-- the fifo_dout bus contains the read data before a read
214 
-- request is actually asserted.  In the case of an empty
215 
-- FIFO, the output data bus is driven by the input data bus.
216 
--
217 
-- If read and write are requested simultaneously to a full
218 
-- FIFO, it will remain full and it operates as an N stage
219 
-- delay line.
220 
--
221 
-- If read and write are requested simultaneously to an empty
222 
-- FIFO, it will remain empty.  No actual access to storage
223 
-- is performed, and the input is simply passed to the output,
224 
-- which could be considered to be a zero stage delay line...
225 
--
226 
-- If the PF empty and full points are set to be overlapping,
227 
-- they can conceivably both be active at the same time.
228 
-- PF empty values less than zero cause the fifo_pf_empty
229 
-- output to stay inactive.  PF full values greater than the
230 
-- FIFO depth cause the fifo_pf_full output to behave exactly
231 
-- the same as fifo_full.
232 
-- There is a third fifo fill level output, fifo_pf_flag.
233 
-- It is high only when the FIFO fill level is greater than
234 
-- or equal to the desired set value.
235 
--
236 
 
237 
library IEEE;
238 
use IEEE.STD_LOGIC_1164.ALL;
239 
use IEEE.NUMERIC_STD.ALL;
240 
use IEEE.MATH_REAL.ALL;
241 
 
242 
library work;
243 
use work.convert_pack.all;
244 
 
245 
entity generic_fifo is
246 
    generic (
247 
      WIDTH          : integer :=  8;
248 
      DEPTH          : integer :=  5;
249 
      PF_FULL_POINT  : integer :=  3;
250 
      PF_FLAG_POINT  : integer :=  2;
251 
      PF_EMPTY_POINT : integer :=  0
252 
    );
253 
    port (
254 
      sys_rst_n     : in  std_logic; -- Asynchronous
255 
      sys_clk       : in  std_logic;
256 
      sys_clk_en    : in  std_logic;
257 
 
258 
      reset_i       : in std_logic;  -- Synchronous
259 
 
260 
      fifo_rd_i     : in  std_logic;
261 
      fifo_dout     : out unsigned(WIDTH-1 downto 0);
262 
 
263 
      fifo_wr_i     : in  std_logic;
264 
      fifo_din      : in  unsigned(WIDTH-1 downto 0);
265 
 
266 
      fifo_full     : out std_logic;
267 
      fifo_empty    : out std_logic;
268 
      fifo_pf_full  : out std_logic;
269 
      fifo_pf_flag  : out std_logic;
270 
      fifo_pf_empty : out std_logic
271 
    );
272 
end generic_fifo;
273 
 
274 
architecture beh of generic_fifo is
275 
 
276 
  -- Constants
277 
  constant FLG_WIDTH : integer := bit_width(DEPTH); -- Bit Width of memory address.  Pointers are one bit wider,
278 
                                                    -- so that fill_level can represent the full quantity of
279 
                                                    -- items stored in the FIFO.  This is important when DEPTH
280 
                                                    -- is an even power of 2.
281 
 
282 
  -- Signal Declarations
283 
  signal rd_row     : unsigned(FLG_WIDTH downto 0);
284 
  signal wr_row     : unsigned(FLG_WIDTH downto 0);
285 
  signal fill_level : unsigned(FLG_WIDTH downto 0);
286 
 
287 
  TYPE memory_array IS
288 
    ARRAY (integer RANGE 0 TO DEPTH-1) OF unsigned(WIDTH-1 DOWNTO 0);
289 
 
290 
  SIGNAL fifo_array: memory_array;
291 
 
292 
  TYPE STATE_TYPE IS (st_empty, st_data, st_full);
293 
 
294 
  signal current_state : STATE_TYPE ;
295 
 
296 
 
297 
BEGIN
298 
 
299 
  fifo_empty    <= '1' when (current_state=st_empty) else '0';
300 
  fifo_full     <= '1' when (current_state=st_full)  else '0';
301 
  fifo_pf_full  <= '1' when (fill_level>=PF_FULL_POINT or current_state=st_full) else '0';
302 
  fifo_pf_flag  <= '1' when (fill_level>=PF_FLAG_POINT) else '0';
303 
  fifo_pf_empty <= '1' when (fill_level<=PF_EMPTY_POINT and current_state/=st_full) else '0';
304 
 
305 
-------------------------
306 
-- The FIFO Fill Level
307 
fill_level_proc: process(wr_row, rd_row, current_state)
308 
  begin
309 
    if (current_state=st_empty) then
310 
      fill_level <= (others=>'0');
311 
    elsif (wr_row>rd_row) then
312 
      fill_level <= wr_row-rd_row;
313 
    else
314 
      fill_level <= DEPTH+(wr_row-rd_row);
315 
    end if;
316 
  end process;
317 
 
318 
-------------------------
319 
-- The FIFO memory
320 
memory: process (sys_clk, sys_rst_n)
321 
  variable i : integer;
322 
  begin
323 
    -- The memory initialization at reset was included for simulation only.
324 
    -- It can be removed for synthesis if desired.
325 
    if (sys_rst_n='0') then
326 
      for i in 0 to DEPTH-1 loop
327 
        fifo_array(i) <= (others=>'0');
328 
      end loop;
329 
    elsif (sys_clk'event and sys_clk = '1') then
330 
      if (sys_clk_en='1') then
331 
        if ((fifo_wr_i='1' and current_state/=st_full) or
332 
            (fifo_wr_i='1' and current_state=st_full and fifo_rd_i='1')) then
333 
          fifo_array(to_integer(wr_row(FLG_WIDTH-1 downto 0))) <= fifo_din;
334 
        end if;
335 
      end if;
336 
    end if;
337 
  end process;
338 
fifo_dout <= fifo_array(to_integer(rd_row(FLG_WIDTH-1 downto 0))) when (current_state/=st_empty)
339 
             else fifo_din;
340 
 
341 
 
342 
-------------------------
343 
-- The FIFO state machine
344 
  clocked : PROCESS(sys_clk, sys_rst_n)
345 
 
346 
  procedure do_write is
347 
  begin
348 
    if (wr_row=DEPTH-1) then  -- Roll buffer index for non-power-of-two
349 
      wr_row <= (others=>'0');
350 
    else
351 
      wr_row<=wr_row+1;
352 
    end if;
353 
  end do_write;
354 
 
355 
  procedure do_read is
356 
  begin
357 
    if (rd_row=DEPTH-1) then  -- Roll buffer index for non-power-of-two
358 
      rd_row <= (others=>'0');
359 
    else
360 
      rd_row<=rd_row+1;
361 
    end if;
362 
  end do_read;
363 
 
364 
  begin
365 
    if (sys_rst_n = '0') then
366 
      current_state <= st_empty;
367 
      rd_row   <= (others=>'0');
368 
      wr_row   <= (others=>'0');
369 
 
370 
    elsif (sys_clk'EVENT and sys_clk = '1') then
371 
      if (sys_clk_en='1') then
372 
        if (reset_i='1') then
373 
          current_state <= st_empty;
374 
          wr_row <= (others=>'0');
375 
          rd_row <= (others=>'0');
376 
        else
377 
          case current_state is
378 
 
379 
          when st_empty =>
380 
            if (fifo_wr_i='1') then
381 
              do_write;
382 
              if (fifo_rd_i='0') then
383 
                current_state<=st_data;
384 
              else
385 
                do_read;
386 
              end if;
387 
            end if;
388 
 
389 
          when st_data =>
390 
            if (fifo_wr_i='1') then
391 
              do_write;
392 
              if (fifo_rd_i='0' and fill_level=DEPTH-1) then
393 
                current_state<=st_full;
394 
              end if;
395 
            end if;
396 
            if (fifo_rd_i='1') then
397 
              do_read;
398 
              if (fifo_wr_i='0' and fill_level=1) then
399 
                current_state<=st_empty;
400 
              end if;
401 
            end if;
402 
 
403 
          when st_full =>
404 
            if (fifo_rd_i='1') then
405 
              do_read;
406 
              if (fifo_wr_i='0') then
407 
                current_state<=st_data;
408 
              else
409 
                do_write;
410 
              end if;
411 
            end if;
412 
 
413 
          when others => null;
414 
          end case;
415 
 
416 
        end if;
417 
      end if; -- sys_clk_en
418 
    end if; -- sys_clk
419 
  end process clocked;
420 
 
421 
 
422 
end beh;
423 
 
424 
 
425 
--------------------------------------------------------------
426 
-- FIFO with fill level output
427 
--------------------------------------------------------------
428 
-- Description:
429 
--
430 
-- This is the same as "generic_fifo" but with an additional
431 
-- output providing the fifo_fill_level.
432 
--
433 
-- The bit width of this additional output is set by a generic
434 
-- parameter
435 
--
436 
--
437 
 
438 
library IEEE;
439 
use IEEE.STD_LOGIC_1164.ALL;
440 
use IEEE.NUMERIC_STD.ALL;
441 
use IEEE.MATH_REAL.ALL;
442 
 
443 
library work;
444 
use work.convert_pack.all;
445 
 
446 
entity fifo_with_fill_level is
447 
    generic (
448 
      WIDTH            : integer :=  8;
449 
      DEPTH            : integer :=  5;
450 
      FILL_LEVEL_BITS  : integer :=  3; -- Should be at least int(floor(log2(DEPTH))+1.0)
451 
      PF_FULL_POINT    : integer :=  3;
452 
      PF_FLAG_POINT    : integer :=  2;
453 
      PF_EMPTY_POINT   : integer :=  0
454 
    );
455 
    port (
456 
      sys_rst_n       : in  std_logic; -- Asynchronous
457 
      sys_clk         : in  std_logic;
458 
      sys_clk_en      : in  std_logic;
459 
 
460 
      reset_i         : in std_logic;  -- Synchronous
461 
 
462 
      fifo_rd_i       : in  std_logic;
463 
      fifo_dout       : out unsigned(WIDTH-1 downto 0);
464 
 
465 
      fifo_wr_i       : in  std_logic;
466 
      fifo_din        : in  unsigned(WIDTH-1 downto 0);
467 
 
468 
      fifo_fill_level : out unsigned(FILL_LEVEL_BITS-1 downto 0);
469 
      fifo_full       : out std_logic;
470 
      fifo_empty      : out std_logic;
471 
      fifo_pf_full    : out std_logic;
472 
      fifo_pf_flag    : out std_logic;
473 
      fifo_pf_empty   : out std_logic
474 
    );
475 
end fifo_with_fill_level;
476 
 
477 
architecture beh of fifo_with_fill_level is
478 
 
479 
  -- Constants
480 
  constant FLG_WIDTH : integer := bit_width(DEPTH); -- Bit Width of memory address.  Pointers are one bit wider,
481 
                                                    -- so that fill_level can represent the full quantity of
482 
                                                    -- items stored in the FIFO.  This is important when DEPTH
483 
                                                    -- is an even power of 2.
484 
 
485 
  -- Signal Declarations
486 
  signal rd_row     : unsigned(FLG_WIDTH downto 0);
487 
  signal wr_row     : unsigned(FLG_WIDTH downto 0);
488 
  signal fill_level : unsigned(FLG_WIDTH downto 0);
489 
 
490 
  TYPE memory_array IS
491 
    ARRAY (integer RANGE 0 TO DEPTH-1) OF unsigned(WIDTH-1 DOWNTO 0);
492 
 
493 
  SIGNAL fifo_array: memory_array;
494 
 
495 
  TYPE STATE_TYPE IS (st_empty, st_data, st_full);
496 
 
497 
  signal current_state : STATE_TYPE ;
498 
 
499 
 
500 
BEGIN
501 
 
502 
  fifo_empty      <= '1' when (current_state=st_empty) else '0';
503 
  fifo_full       <= '1' when (current_state=st_full)  else '0';
504 
  fifo_pf_full    <= '1' when (fill_level>=PF_FULL_POINT or current_state=st_full) else '0';
505 
  fifo_pf_flag    <= '1' when (fill_level>=PF_FLAG_POINT) else '0';
506 
  fifo_pf_empty   <= '1' when (fill_level<=PF_EMPTY_POINT and current_state/=st_full) else '0';
507 
  fifo_fill_level <= u_resize(fill_level,FILL_LEVEL_BITS);
508 
 
509 
-------------------------
510 
-- The FIFO Fill Level
511 
fill_level_proc: process(wr_row, rd_row, current_state)
512 
  begin
513 
    if (current_state=st_empty) then
514 
      fill_level <= (others=>'0');
515 
    elsif (wr_row>rd_row) then
516 
      fill_level <= wr_row-rd_row;
517 
    else
518 
      fill_level <= DEPTH+(wr_row-rd_row);
519 
    end if;
520 
  end process;
521 
 
522 
-------------------------
523 
-- The FIFO memory
524 
memory: process (sys_clk, sys_rst_n)
525 
  variable i : integer;
526 
  begin
527 
    -- The memory initialization at reset was included for simulation only.
528 
    -- It can be removed for synthesis if desired.
529 
    if (sys_rst_n='0') then
530 
      for i in 0 to DEPTH-1 loop
531 
        fifo_array(i) <= (others=>'0');
532 
      end loop;
533 
    elsif (sys_clk'event and sys_clk = '1') then
534 
      if (sys_clk_en='1') then
535 
        if ((fifo_wr_i='1' and current_state/=st_full) or
536 
            (fifo_wr_i='1' and current_state=st_full and fifo_rd_i='1')) then
537 
          fifo_array(to_integer(wr_row(FLG_WIDTH-1 downto 0))) <= fifo_din;
538 
        end if;
539 
      end if;
540 
    end if;
541 
end process;
542 
fifo_dout <= fifo_array(to_integer(rd_row(FLG_WIDTH-1 downto 0))) when (current_state/=st_empty)
543 
             else fifo_din;
544 
 
545 
 
546 
-------------------------
547 
-- The FIFO state machine
548 
  clocked : PROCESS(sys_clk, sys_rst_n)
549 
 
550 
  procedure do_write is
551 
  begin
552 
    if (wr_row=DEPTH-1) then  -- Roll buffer index for non-power-of-two
553 
      wr_row <= (others=>'0');
554 
    else
555 
      wr_row<=wr_row+1;
556 
    end if;
557 
  end do_write;
558 
 
559 
  procedure do_read is
560 
  begin
561 
    if (rd_row=DEPTH-1) then  -- Roll buffer index for non-power-of-two
562 
      rd_row <= (others=>'0');
563 
    else
564 
      rd_row<=rd_row+1;
565 
    end if;
566 
  end do_read;
567 
 
568 
  begin
569 
    if (sys_rst_n = '0') then
570 
      current_state <= st_empty;
571 
      rd_row   <= (others=>'0');
572 
      wr_row   <= (others=>'0');
573 
 
574 
    elsif (sys_clk'EVENT and sys_clk = '1') then
575 
      if (sys_clk_en='1') then
576 
        if (reset_i='1') then
577 
          current_state <= st_empty;
578 
          wr_row <= (others=>'0');
579 
          rd_row <= (others=>'0');
580 
        else
581 
          case current_state is
582 
 
583 
          when st_empty =>
584 
            if (fifo_wr_i='1') then
585 
              do_write;
586 
              if (fifo_rd_i='0') then
587 
                current_state<=st_data;
588 
              else
589 
                do_read;
590 
              end if;
591 
            end if;
592 
 
593 
          when st_data =>
594 
            if (fifo_wr_i='1') then
595 
              do_write;
596 
              if (fifo_rd_i='0' and fill_level=DEPTH-1) then
597 
                current_state<=st_full;
598 
              end if;
599 
            end if;
600 
            if (fifo_rd_i='1') then
601 
              do_read;
602 
              if (fifo_wr_i='0' and fill_level=1) then
603 
                current_state<=st_empty;
604 
              end if;
605 
            end if;
606 
 
607 
          when st_full =>
608 
            if (fifo_rd_i='1') then
609 
              do_read;
610 
              if (fifo_wr_i='0') then
611 
                current_state<=st_data;
612 
              else
613 
                do_write;
614 
              end if;
615 
            end if;
616 
 
617 
          when others => null;
618 
          end case;
619 
 
620 
        end if;
621 
      end if; -- sys_clk_en
622 
    end if; -- sys_clk
623 
  end process clocked;
624 
 
625 
 
626 
end beh;
627 
 
628 
 
629 
--------------------------------------------------------------
630 
-- SWISS ARMY FIFO with fill level output
631 
--------------------------------------------------------------
632 
-- Description:
633 
--
634 
-- This is the same as "fifo_with_fill_level" but it has been
635 
-- coded to select whether Block RAMs or distributed RAMs are inferred.
636 
--
637 
-- The bit width of this additional output is set by a generic
638 
-- parameter
639 
--
640 
-- Note : When USE_BRAM=0, the behavior when reading the FIFO is to
641 
--        make read data available immediately during the clock cycle
642 
--        in which fifo_rd_i='1'.  When USE_BRAM/=0, then an additional
643 
--        clock cycle occurs following the fifo_rd_i pulse, before the
644 
--        output data is available.
645 
--        Please be aware of this.
646 
--
647 
--
648 
 
649 
library IEEE;
650 
use IEEE.STD_LOGIC_1164.ALL;
651 
use IEEE.NUMERIC_STD.ALL;
652 
use IEEE.MATH_REAL.ALL;
653 
 
654 
library work;
655 
use work.convert_pack.all;
656 
use work.block_ram_pack.all;
657 
 
658 
entity swiss_army_fifo is
659 
    generic (
660 
      USE_BRAM         : integer :=  1; -- Set to nonzero value for BRAM, zero for distributed RAM
661 
      WIDTH            : integer :=  8;
662 
      DEPTH            : integer :=  5;
663 
      FILL_LEVEL_BITS  : integer :=  3; -- Should be at least int(floor(log2(DEPTH))+1.0)
664 
      PF_FULL_POINT    : integer :=  3;
665 
      PF_FLAG_POINT    : integer :=  2;
666 
      PF_EMPTY_POINT   : integer :=  0
667 
    );
668 
    port (
669 
      sys_rst_n       : in  std_logic; -- Asynchronous
670 
      sys_clk         : in  std_logic;
671 
      sys_clk_en      : in  std_logic;
672 
 
673 
      reset_i         : in  std_logic;  -- Synchronous
674 
 
675 
      fifo_wr_i       : in  std_logic;
676 
      fifo_din        : in  unsigned(WIDTH-1 downto 0);
677 
 
678 
      fifo_rd_i       : in  std_logic;
679 
      fifo_dout       : out unsigned(WIDTH-1 downto 0);
680 
 
681 
      fifo_fill_level : out unsigned(FILL_LEVEL_BITS-1 downto 0);
682 
      fifo_full       : out std_logic;
683 
      fifo_empty      : out std_logic;
684 
      fifo_pf_full    : out std_logic;
685 
      fifo_pf_flag    : out std_logic;
686 
      fifo_pf_empty   : out std_logic
687 
    );
688 
end swiss_army_fifo;
689 
 
690 
architecture beh of swiss_army_fifo is
691 
 
692 
  -- Constants
693 
  constant FLG_WIDTH : integer := bit_width(DEPTH); -- Bit Width of memory address.  Pointers are one bit wider,
694 
                                                    -- so that fill_level can represent the full quantity of
695 
                                                    -- items stored in the FIFO.  This is important when DEPTH
696 
                                                    -- is an even power of 2.
697 
 
698 
  -- Signal Declarations
699 
  signal rd_row     : unsigned(FLG_WIDTH downto 0);
700 
  signal wr_row     : unsigned(FLG_WIDTH downto 0);
701 
  signal fill_level : unsigned(FLG_WIDTH downto 0);
702 
  signal ram_we_a   : std_logic;
703 
  signal ram_dout   : unsigned(WIDTH-1 downto 0);
704 
 
705 
  TYPE STATE_TYPE IS (st_empty, st_data, st_full);
706 
  signal current_state : STATE_TYPE ;
707 
 
708 
  signal bram_dat_b : unsigned(WIDTH-1 downto 0);
709 
 
710 
BEGIN
711 
 
712 
  fifo_empty      <= '1' when (current_state=st_empty) else '0';
713 
  fifo_full       <= '1' when (current_state=st_full)  else '0';
714 
  fifo_pf_full    <= '1' when (fill_level>=PF_FULL_POINT or current_state=st_full) else '0';
715 
  fifo_pf_flag    <= '1' when (fill_level>=PF_FLAG_POINT) else '0';
716 
  fifo_pf_empty   <= '1' when (fill_level<=PF_EMPTY_POINT and current_state/=st_full) else '0';
717 
  fifo_fill_level <= u_resize(fill_level,FILL_LEVEL_BITS);
718 
 
719 
-------------------------
720 
-- The FIFO Fill Level
721 
fill_level_proc: process(wr_row, rd_row, current_state)
722 
  begin
723 
    if (current_state=st_empty) then
724 
      fill_level <= (others=>'0');
725 
    elsif (wr_row>rd_row) then
726 
      fill_level <= wr_row-rd_row;
727 
    else
728 
      fill_level <= DEPTH+(wr_row-rd_row);
729 
    end if;
730 
  end process;
731 
 
732 
-------------------------
733 
-- The FIFO memory
734 
 
735 
-- Port A is the write side.
736 
-- Port B is dedicated to reading only.
737 
-- The hexfile is used to permit initialization of the RAM
738 
 
739 
  fifo_ram : swiss_army_ram
740 
    generic map(
741 
      USE_BRAM  => USE_BRAM,
742 
      WRITETHRU => 0, -- Set to nonzero value for writethrough mode
743 
      USE_FILE  => 0, -- Set to nonzero value to use INIT_FILE
744 
      INIT_VAL  => 0,
745 
      INIT_SEL  => 0, -- No generate loop here
746 
      INIT_FILE => ".\foo.txt", -- ASCII hexadecimal initialization file name
747 
      FIL_WIDTH => 32, -- Bit width of init file lines
748 
      ADR_WIDTH => FLG_WIDTH,
749 
      DAT_WIDTH => WIDTH
750 
    )
751 
    port map (
752 
       clk_a    => sys_clk,
753 
       clk_b    => sys_clk,
754 
 
755 
       adr_a_i  => wr_row(FLG_WIDTH-1 downto 0),
756 
       adr_b_i  => rd_row(FLG_WIDTH-1 downto 0),
757 
 
758 
       we_a_i   => ram_we_a,
759 
       en_a_i   => sys_clk_en,
760 
       dat_a_i  => fifo_din,
761 
       dat_a_o  => open,
762 
 
763 
       we_b_i   => '0',
764 
       en_b_i   => sys_clk_en,
765 
       dat_b_i  => bram_dat_b,
766 
       dat_b_o  => ram_dout
767 
    );
768 
 
769 
  bram_dat_b <= (others=>'0');
770 
  ram_we_a <= '1' when fifo_wr_i='1' and (current_state/=st_full or (current_state=st_full and fifo_rd_i='1')) else '0';
771 
  fifo_dout <= ram_dout;
772 
 
773 
 
774 
-------------------------
775 
-- The FIFO state machine
776 
  clocked : PROCESS(sys_clk, sys_rst_n)
777 
 
778 
  procedure do_write is
779 
  begin
780 
    if (wr_row=DEPTH-1) then  -- Roll buffer index for non-power-of-two
781 
      wr_row <= (others=>'0');
782 
    else
783 
      wr_row<=wr_row+1;
784 
    end if;
785 
  end do_write;
786 
 
787 
  procedure do_read is
788 
  begin
789 
    if (rd_row=DEPTH-1) then  -- Roll buffer index for non-power-of-two
790 
      rd_row <= (others=>'0');
791 
    else
792 
      rd_row<=rd_row+1;
793 
    end if;
794 
  end do_read;
795 
 
796 
  begin
797 
    if (sys_rst_n = '0') then
798 
      current_state <= st_empty;
799 
      rd_row   <= (others=>'0');
800 
      wr_row   <= (others=>'0');
801 
 
802 
    elsif (sys_clk'EVENT and sys_clk = '1') then
803 
      if (sys_clk_en='1') then
804 
        if (reset_i='1') then
805 
          current_state <= st_empty;
806 
          wr_row <= (others=>'0');
807 
          rd_row <= (others=>'0');
808 
        else
809 
          case current_state is
810 
 
811 
          -- When empty, one can only read if also writing
812 
          when st_empty =>
813 
            if (fifo_wr_i='1') then
814 
              do_write;
815 
              if (fifo_rd_i='1') then
816 
                do_read;
817 
              else
818 
                current_state<=st_data;
819 
              end if;
820 
            end if;
821 
 
822 
          when st_data =>
823 
            if (fifo_wr_i='1') then
824 
              do_write;
825 
              if (fifo_rd_i='0' and fill_level=DEPTH-1) then
826 
                current_state<=st_full;
827 
              end if;
828 
            end if;
829 
            if (fifo_rd_i='1') then
830 
              do_read;
831 
              if (fifo_wr_i='0' and fill_level=1) then
832 
                current_state<=st_empty;
833 
              end if;
834 
            end if;
835 
 
836 
          -- When full, one can only write if also reading
837 
          when st_full =>
838 
            if (fifo_rd_i='1') then
839 
              do_read;
840 
              if (fifo_wr_i='1') then
841 
                do_write;
842 
              else
843 
                current_state<=st_data;
844 
              end if;
845 
            end if;
846 
 
847 
          when others => null;
848 
          end case;
849 
 
850 
        end if;
851 
      end if; -- sys_clk_en
852 
    end if; -- sys_clk
853 
  end process clocked;
854 
 
855 
 
856 
end beh;
857 
 
858 
--------------------------------------------------------------
859 
-- SWISS ARMY FIFO "Clock Domain Crossing" version
860 
--------------------------------------------------------------
861 
-- Description:
862 
--
863 
-- This is the same as "swiss_army_fifo" but it has been
864 
-- coded to include two separate clock domains.  Originally,
865 
-- the status signals were all synchronized to their respective
866 
-- clock domains.  However, it was taken out so that the user of
867 
-- this module must take care as the status signals are not delayed,
868 
-- but they are possibly subject to metastability.
869 
--
870 
-- Note : When USE_BRAM=0, the behavior when reading the FIFO is to
871 
--        make read data available immediately during the clock cycle
872 
--        in which fifo_rd_i='1'.  When USE_BRAM/=0, then an additional
873 
--        clock cycle occurs following the fifo_rd_i pulse, before the
874 
--        output data is available.
875 
--        Please be aware of this.
876 
--
877 
--
878 
 
879 
library IEEE;
880 
use IEEE.STD_LOGIC_1164.ALL;
881 
use IEEE.NUMERIC_STD.ALL;
882 
use IEEE.MATH_REAL.ALL;
883 
 
884 
library work;
885 
use work.convert_pack.all;
886 
use work.block_ram_pack.all;
887 
 
888 
entity swiss_army_fifo_cdc is
889 
    generic (
890 
      USE_BRAM         : integer :=  1; -- Set to nonzero value for BRAM, zero for distributed RAM
891 
      WIDTH            : integer :=  8;
892 
      DEPTH            : integer :=  5;
893 
      FILL_LEVEL_BITS  : integer :=  3; -- Should be at least int(floor(log2(DEPTH))+1.0)
894 
      PF_FULL_POINT    : integer :=  3;
895 
      PF_FLAG_POINT    : integer :=  2;
896 
      PF_EMPTY_POINT   : integer :=  0
897 
    );
898 
    port (
899 
      sys_rst_n        : in  std_logic; -- Asynchronous
900 
 
901 
      wr_clk_i         : in  std_logic;
902 
      wr_clk_en_i      : in  std_logic;
903 
      wr_reset_i       : in  std_logic;  -- Synchronous
904 
      wr_en_i          : in  std_logic;
905 
      wr_dat_i         : in  unsigned(WIDTH-1 downto 0);
906 
      wr_fifo_level    : out unsigned(FILL_LEVEL_BITS-1 downto 0);
907 
      wr_fifo_full     : out std_logic;
908 
      wr_fifo_empty    : out std_logic;
909 
      wr_fifo_pf_full  : out std_logic;
910 
      wr_fifo_pf_flag  : out std_logic;
911 
      wr_fifo_pf_empty : out std_logic;
912 
 
913 
      rd_clk_i         : in  std_logic;
914 
      rd_clk_en_i      : in  std_logic;
915 
      rd_reset_i       : in  std_logic;  -- Synchronous
916 
      rd_en_i          : in  std_logic;
917 
      rd_dat_o         : out unsigned(WIDTH-1 downto 0);
918 
      rd_fifo_level    : out unsigned(FILL_LEVEL_BITS-1 downto 0);
919 
      rd_fifo_full     : out std_logic;
920 
      rd_fifo_empty    : out std_logic;
921 
      rd_fifo_pf_full  : out std_logic;
922 
      rd_fifo_pf_flag  : out std_logic;
923 
      rd_fifo_pf_empty : out std_logic
924 
 
925 
    );
926 
end swiss_army_fifo_cdc;
927 
 
928 
architecture beh of swiss_army_fifo_cdc is
929 
 
930 
  -- Constants
931 
  constant FLG_WIDTH : integer := bit_width(DEPTH); -- Bit Width of memory address.  Pointers are one bit wider,
932 
                                                    -- so that fill_level can represent the full quantity of
933 
                                                    -- items stored in the FIFO.  This is important when DEPTH
934 
                                                    -- is an even power of 2.
935 
 
936 
  -- Signal Declarations
937 
  signal rd_row     : unsigned(FLG_WIDTH downto 0);
938 
  signal wr_row     : unsigned(FLG_WIDTH downto 0);
939 
  signal fill_level : unsigned(FLG_WIDTH+1 downto 0);
940 
  signal ram_we_a   : std_logic;
941 
  signal bram_dat_b : unsigned(WIDTH-1 downto 0);
942 
 
943 
  signal fifo_level       : unsigned(FILL_LEVEL_BITS-1 downto 0);
944 
  signal fifo_full        : std_logic;
945 
  signal fifo_empty       : std_logic;
946 
  signal fifo_pf_full     : std_logic;
947 
  signal fifo_pf_flag     : std_logic;
948 
  signal fifo_pf_empty    : std_logic;
949 
 
950 
begin
951 
 
952 
  fifo_level    <= u_resize(fill_level,FILL_LEVEL_BITS);
953 
  fifo_full     <= '1' when (fill_level=DEPTH) else '0';
954 
  fifo_empty    <= '1' when (fill_level=0) else '0';
955 
  fifo_pf_full  <= '1' when (fill_level>=PF_FULL_POINT) else '0';
956 
  fifo_pf_flag  <= '1' when (fill_level>=PF_FLAG_POINT) else '0';
957 
  fifo_pf_empty <= '1' when (fill_level<=PF_EMPTY_POINT) else '0';
958 
 
959 
-------------------------
960 
-- The FIFO Fill Level
961 
 
962 
fill_level <= (others=>'0') when wr_row=rd_row else
963 
              ('0' & wr_row)-('0' & rd_row) when wr_row>rd_row else
964 
              (2**(FLG_WIDTH+1))+(('0' & wr_row)-('0' & rd_row));
965 
 
966 
-------------------------
967 
-- The FIFO memory
968 
 
969 
-- Port A is the write side.
970 
-- Port B is dedicated to reading only.
971 
-- The hexfile is used to permit initialization of the RAM
972 
 
973 
  fifo_ram : swiss_army_ram
974 
    generic map(
975 
      USE_BRAM  => USE_BRAM,
976 
      WRITETHRU => 0, -- Set to nonzero value for writethrough mode
977 
      USE_FILE  => 0, -- Set to nonzero value to use INIT_FILE
978 
      INIT_VAL  => 0,
979 
      INIT_SEL  => 0, -- No generate loop here
980 
      INIT_FILE => ".\foo.txt", -- ASCII hexadecimal initialization file name
981 
      FIL_WIDTH => 32, -- Bit width of init file lines
982 
      ADR_WIDTH => FLG_WIDTH,
983 
      DAT_WIDTH => WIDTH
984 
    )
985 
    port map (
986 
       clk_a    => wr_clk_i,
987 
       clk_b    => rd_clk_i,
988 
 
989 
       adr_a_i  => wr_row(FLG_WIDTH-1 downto 0),
990 
       adr_b_i  => rd_row(FLG_WIDTH-1 downto 0),
991 
 
992 
       we_a_i   => ram_we_a,
993 
       en_a_i   => wr_clk_en_i,
994 
       dat_a_i  => wr_dat_i,
995 
       dat_a_o  => open,
996 
 
997 
       we_b_i   => '0',
998 
       en_b_i   => rd_clk_en_i,
999 
       dat_b_i  => bram_dat_b,
1000 
       dat_b_o  => rd_dat_o
1001 
    );
1002 
 
1003 
  bram_dat_b <= (others=>'0');
1004 
  ram_we_a <= '1' when wr_en_i='1' and fifo_full='0' else '0';
1005 
 
1006 
-------------------------
1007 
-- The FIFO writing process
1008 
  wr_proc : PROCESS(wr_clk_i, sys_rst_n)
1009 
  begin
1010 
    if (sys_rst_n = '0') then
1011 
      wr_row   <= (others=>'0');
1012 
    elsif (wr_clk_i'event and wr_clk_i = '1') then
1013 
      if (wr_clk_en_i='1') then
1014 
        if (wr_reset_i='1') then
1015 
          wr_row <= (others=>'0');
1016 
        else
1017 
          if (ram_we_a='1') then
1018 
            if (fifo_level=DEPTH) then
1019 
              null; -- FIFO is full!  Don't do any writes.
1020 
            else
1021 
              wr_row <= wr_row+1;
1022 
            end if;
1023 
          end if;
1024 
        end if;
1025 
        -- Synchronize all dataflow outputs to the
1026 
        -- wr_clk_i clock domain
1027 
--        wr_fifo_level    <= fifo_level;
1028 
--        wr_fifo_full     <= fifo_full;
1029 
--        wr_fifo_empty    <= fifo_empty;
1030 
--        wr_fifo_pf_full  <= fifo_pf_full;
1031 
--        wr_fifo_pf_flag  <= fifo_pf_flag;
1032 
--        wr_fifo_pf_empty <= fifo_pf_empty;
1033 
      end if; -- wr_clk_en
1034 
    end if; -- wr_clk_i
1035 
  end process wr_proc;
1036 
  -- Synchronized version removed, because it added an extra clock
1037 
  -- cycle of delay.
1038 
  -- This may be dangerous in terms of flip-flop metastability
1039 
  wr_fifo_level    <= fifo_level;
1040 
  wr_fifo_full     <= fifo_full;
1041 
  wr_fifo_empty    <= fifo_empty;
1042 
  wr_fifo_pf_full  <= fifo_pf_full;
1043 
  wr_fifo_pf_flag  <= fifo_pf_flag;
1044 
  wr_fifo_pf_empty <= fifo_pf_empty;
1045 
 
1046 
-------------------------
1047 
-- The FIFO reading process
1048 
  rd_proc : PROCESS(rd_clk_i, sys_rst_n)
1049 
  begin
1050 
    if (sys_rst_n = '0') then
1051 
      rd_row   <= (others=>'0');
1052 
    elsif (rd_clk_i'event and rd_clk_i = '1') then
1053 
      if (rd_clk_en_i='1') then
1054 
        if (rd_reset_i='1') then
1055 
          rd_row <= (others=>'0');
1056 
        else
1057 
          if (rd_en_i='1' and fifo_empty='0') then
1058 
            if (fifo_level=0) then
1059 
              null; -- FIFO is empty!  Don't read anything.
1060 
            else
1061 
              rd_row <= rd_row+1;
1062 
            end if;
1063 
          end if;
1064 
        end if;
1065 
        -- Synchronize all dataflow outputs to the
1066 
        -- rd_clk_i clock domain
1067 
--        rd_fifo_level    <= fifo_level;
1068 
--        rd_fifo_full     <= fifo_full;
1069 
--        rd_fifo_empty    <= fifo_empty;
1070 
--        rd_fifo_pf_full  <= fifo_pf_full;
1071 
--        rd_fifo_pf_flag  <= fifo_pf_flag;
1072 
--        rd_fifo_pf_empty <= fifo_pf_empty;
1073 
      end if; -- rd_clk_en
1074 
    end if; -- rd_clk_i
1075 
  end process rd_proc;
1076 
  -- Synchronized version removed, because it added an extra clock
1077 
  -- cycle of delay.
1078 
  -- This may be dangerous in terms of flip-flop metastability
1079 
  rd_fifo_level    <= fifo_level;
1080 
  rd_fifo_full     <= fifo_full;
1081 
  rd_fifo_empty    <= fifo_empty;
1082 
  rd_fifo_pf_full  <= fifo_pf_full;
1083 
  rd_fifo_pf_flag  <= fifo_pf_flag;
1084 
  rd_fifo_pf_empty <= fifo_pf_empty;
1085 
 
1086 
end beh;
1087 
 
1088 
-------------------------------------------------------------------------------
1089 
-- Adjustable Data Packer
1090 
-------------------------------------------------------------------------------
1091 
--
1092 
-- Author: John Clayton
1093 
-- Date  : Sep.  04, 2012  Copied code from pcm_tx, and began
1094 
--                         updating the description.
1095 
--         July  18, 2013  Moved this module from decom_pack into
1096 
--                         fifo_pack, and revised the description
1097 
--                         to make it sound more generic.
1098 
--
1099 
-- Description
1100 
-------------------------------------------------------------------------------
1101 
-- This module is a very simple "bit packer" that takes in data on a parallel
1102 
-- bus, along with a word size value that indicates which of the input least
1103 
-- significant bits are to be "packed."
1104 
--
1105 
-- The input port is an address snooper, meaning that it is intended to be used
1106 
-- on a bus with other units also receiving the data.  The other units will
1107 
-- acknowledge the transfers, and this unit uses that acknowledge to latch the
1108 
-- bus data.
1109 
--
1110 
-- The latched input word is shifted one bit at a time into the output
1111 
-- word shift register.  When the output word shift register is full, the
1112 
-- output word is latched, and an output cycle is produced.
1113 
--
1114 
-- This mechanism allows data words of dynamically programmable size to be
1115 
-- "snooped up" for any selected data source on the input bus, and then sent
1116 
-- over the ethernet interface as 8-bit values.
1117 
--
1118 
-- When asserted, the "last word" input causes zero bits to be packed into the
1119 
-- output word as needed to finish up a final output cycle.
1120 
 
1121 
library IEEE;
1122 
use IEEE.STD_LOGIC_1164.ALL;
1123 
use IEEE.NUMERIC_STD.ALL;
1124 
use IEEE.MATH_REAL.ALL;
1125 
 
1126 
library work;
1127 
use work.fifo_pack.all;
1128 
use work.convert_pack.all;
1129 
 
1130 
  entity data_packer is
1131 
    generic (
1132 
      ADR_W          : integer :=   4; -- Bit width of snoop address
1133 
      DATA_IN_W      : integer :=  16; -- Maximum in_dat_i word size
1134 
      LOG2_DATA_IN_W : integer :=   4; -- Bit width of in_word_size_i
1135 
      DATA_OUT_W     : integer :=   8; -- Bit width of archive data
1136 
      FIFO_DEPTH     : integer := 512  -- Size of BRAM FIFO buffer
1137 
    );
1138 
    port (
1139 
 
1140 
      sys_rst_n  : in std_logic;
1141 
      sys_clk    : in std_logic;
1142 
      sys_clk_en : in std_logic;
1143 
 
1144 
      -- Input Port
1145 
      in_dat_i        : in  unsigned(DATA_IN_W-1 downto 0);
1146 
      in_word_size_i  : in  unsigned(LOG2_DATA_IN_W downto 0);
1147 
      in_last_word_i  : in  std_logic;
1148 
      in_adr_i        : in  unsigned(ADR_W-1 downto 0);
1149 
      in_match_adr_i  : in  unsigned(ADR_W-1 downto 0);
1150 
      in_cyc_i        : in  std_logic;
1151 
      in_ack_i        : in  std_logic;
1152 
 
1153 
      -- Status
1154 
      fifo_full_o     : out std_logic;
1155 
      fifo_reset_i    : in  std_logic;
1156 
 
1157 
      -- Output Port
1158 
      tx_done_i       : in  std_logic;
1159 
      tx_buff_i       : in  unsigned(ADR_W-1 downto 0);
1160 
      out_dat_o       : out unsigned(DATA_OUT_W-1 downto 0);
1161 
      out_last_word_o : out std_logic;
1162 
      out_cyc_o       : out std_logic;
1163 
      out_ack_i       : in  std_logic
1164 
 
1165 
    );
1166 
  end data_packer;
1167 
 
1168 
architecture beh of data_packer is
1169 
 
1170 
-- Constants
1171 
constant FIFO_WIDTH      : natural := (LOG2_DATA_IN_W+1)+DATA_IN_W+1; -- word_size, data, 1 bit last word flag
1172 
constant FIFO_FILL_BITS  : natural := timer_width(FIFO_DEPTH);
1173 
constant LOG2_DATA_OUT_W : natural := bit_width(DATA_OUT_W);
1174 
 
1175 
-- Internal signal declarations
1176 
signal fifo_din         : unsigned(FIFO_WIDTH-1 downto 0);
1177 
signal fifo_dout        : unsigned(FIFO_WIDTH-1 downto 0);
1178 
signal fifo_we          : std_logic;
1179 
signal fifo_rd          : std_logic;
1180 
signal fifo_empty       : std_logic;
1181 
signal stored_data      : unsigned(DATA_IN_W-1 downto 0);
1182 
signal stored_word_size : unsigned(LOG2_DATA_IN_W downto 0);
1183 
signal stored_last_word : std_logic;
1184 
 
1185 
  -- Modified Miller Code State Machine
1186 
type FSM_STATE_TYPE is (TRANSFER, READ_DATA, MAKE_TAIL, WRITE_DATA, WRITE_LAST_DATA);
1187 
signal fsm_state        : FSM_STATE_TYPE;
1188 
 
1189 
 
1190 
 
1191 
signal bits_in        : unsigned(DATA_IN_W downto 0); -- includes "last word" bit
1192 
signal bits_in_count  : unsigned(LOG2_DATA_IN_W downto 0);
1193 
signal bit_sel        : unsigned(LOG2_DATA_IN_W downto 0);
1194 
signal bits_out       : unsigned(DATA_OUT_W-1 downto 0);
1195 
signal bits_out_count : unsigned(LOG2_DATA_OUT_W downto 0);
1196 
signal transfer_bit   : std_logic;
1197 
signal buffering      : std_logic;
1198 
 
1199 
begin
1200 
 
1201 
fifo_din <= in_word_size_i & in_dat_i & in_last_word_i;
1202 
fifo_we  <= '1' when (in_adr_i=in_match_adr_i) and in_cyc_i='1' and in_ack_i='1' else '0';
1203 
stored_word_size <= fifo_dout(DATA_IN_W+1+LOG2_DATA_IN_W downto DATA_IN_W+1);
1204 
stored_data      <= fifo_dout(DATA_IN_W downto 1);
1205 
stored_last_word <= fifo_dout(0);
1206 
 
1207 
packer_fifo : swiss_army_fifo
1208 
  generic map(
1209 
    USE_BRAM         => 1,
1210 
    WIDTH            => FIFO_WIDTH,
1211 
    DEPTH            => FIFO_DEPTH,
1212 
    FILL_LEVEL_BITS  => FIFO_FILL_BITS,
1213 
    PF_FULL_POINT    => FIFO_DEPTH-4,
1214 
    PF_FLAG_POINT    => FIFO_DEPTH/2,
1215 
    PF_EMPTY_POINT   => 4
1216 
  )
1217 
  port map(
1218 
    sys_rst_n       => sys_rst_n,
1219 
    sys_clk         => sys_clk,
1220 
    sys_clk_en      => sys_clk_en,
1221 
 
1222 
    reset_i         => fifo_reset_i,
1223 
 
1224 
    fifo_wr_i       => fifo_we,
1225 
    fifo_din        => fifo_din,
1226 
 
1227 
    fifo_rd_i       => fifo_rd,
1228 
    fifo_dout       => fifo_dout,
1229 
 
1230 
    fifo_fill_level => open,
1231 
    fifo_full       => fifo_full_o,
1232 
    fifo_empty      => fifo_empty,
1233 
    fifo_pf_full    => open,
1234 
    fifo_pf_flag    => open,
1235 
    fifo_pf_empty   => open
1236 
  );
1237 
 
1238 
pack_proc: process(sys_clk, sys_rst_n)
1239 
begin
1240 
  if (sys_rst_n='0') then
1241 
    buffering       <= '1';
1242 
    bits_in         <= (others=>'0');
1243 
    bits_in_count   <= (others=>'0');
1244 
    bits_out        <= (others=>'0');
1245 
    bits_out_count  <= (others=>'0');
1246 
    bit_sel         <= (others=>'0');
1247 
    fsm_state       <= READ_DATA;
1248 
  elsif (sys_clk'event and sys_clk='1') then
1249 
    if (sys_clk_en='1') then
1250 
 
1251 
      -- Handle transitions from packing state to buffering state
1252 
      if (tx_done_i='1' and tx_buff_i=in_match_adr_i) then
1253 
        buffering <= '0';
1254 
      end if;
1255 
 
1256 
      if (buffering='0') then
1257 
 
1258 
        -- Default values
1259 
 
1260 
        -- Handle state transitions
1261 
        case (fsm_state) is
1262 
 
1263 
          when TRANSFER =>
1264 
            if (bits_in_count=0) then
1265 
              if (transfer_bit='1') then -- Check last word bit.
1266 
                fsm_state <= MAKE_TAIL;
1267 
              else
1268 
                fsm_state <= READ_DATA;
1269 
              end if;
1270 
              -- Writing completed data is highest priority
1271 
              if (bits_out_count=DATA_OUT_W) then
1272 
                if (transfer_bit='1') then
1273 
                  fsm_state <= WRITE_LAST_DATA;
1274 
                  bits_out_count <= (others=>'0');
1275 
                else
1276 
                  fsm_state <= WRITE_DATA;
1277 
                  bits_out_count <= (others=>'0');
1278 
                end if;
1279 
              end if;
1280 
            elsif (bits_out_count=DATA_OUT_W) then
1281 
              fsm_state <= WRITE_DATA;
1282 
              bits_out_count <= (others=>'0');
1283 
            elsif (bits_in_count>0) then
1284 
              bits_out <= bits_out(bits_out'length-2 downto 0) & transfer_bit;
1285 
              bits_in  <= bits_in(bits_in'length-2 downto 0) & '0';
1286 
              bits_in_count <= bits_in_count-1;
1287 
              bits_out_count <= bits_out_count+1;
1288 
            end if;
1289 
 
1290 
          when READ_DATA =>
1291 
            bits_in       <= stored_data & stored_last_word;
1292 
            bits_in_count <= stored_word_size;
1293 
            bit_sel       <= stored_word_size;
1294 
            if (fifo_rd='1' and stored_word_size>0) then
1295 
              fsm_state <= TRANSFER;
1296 
            end if;
1297 
 
1298 
          when MAKE_TAIL =>
1299 
            if (bits_out_count>=DATA_OUT_W) then
1300 
              fsm_state <= WRITE_LAST_DATA;
1301 
              bits_out_count <= (others=>'0');
1302 
            else
1303 
              bits_out <= bits_out(DATA_OUT_W-2 downto 0) & '0';
1304 
              bits_out_count <= bits_out_count+1;
1305 
            end if;
1306 
 
1307 
          when WRITE_DATA =>
1308 
            if (out_ack_i='1') then
1309 
              fsm_state <= TRANSFER;
1310 
              if (bits_in_count=0) then
1311 
                fsm_state <= READ_DATA;
1312 
              end if;
1313 
            end if;
1314 
 
1315 
          when WRITE_LAST_DATA =>
1316 
            if (out_ack_i='1') then
1317 
              fsm_state <= TRANSFER;
1318 
              if (bits_in_count=0) then
1319 
                fsm_state <= READ_DATA;
1320 
              end if;
1321 
              buffering <= '1';
1322 
            end if;
1323 
 
1324 
          --when others =>
1325 
          --  fsm_state <= IDLE;
1326 
        end case;
1327 
 
1328 
      end if; -- buffering='0' and fifo_empty='0'
1329 
 
1330 
    end if; -- sys_clk_en
1331 
  end if; -- sys_clk
1332 
end process;
1333 
 
1334 
-- Select the correct bit to transfer
1335 
transfer_bit <= bits_in(to_integer(bit_sel));
1336 
 
1337 
-- Create FIFO read signal
1338 
fifo_rd <= '1' when fsm_state=READ_DATA and fifo_empty='0' and buffering='0' else '0';
1339 
 
1340 
-- Assign the outputs
1341 
out_last_word_o <= '1' when fsm_state=WRITE_LAST_DATA else '0';
1342 
out_cyc_o <= '1' when fsm_state=WRITE_DATA or fsm_state=WRITE_LAST_DATA else '0';
1343 
out_dat_o <= bits_out;
1344 
 
1345 
end beh;
1346 
 

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