1 ----------------------------------------------------------------------------------
2 -- Company: VISENGI S.L. (www.visengi.com) - URJC FRAV Group (www.frav.es)
3 -- Engineer: Victor Lopez Lorenzo (victor.lopez (at) visengi (dot) com)
5 -- Create Date: 12:39:50 06-Oct-2008
6 -- Project Name: ZBT SRAM WISHBONE Controller
7 -- Target Devices: Xilinx ML506 board
8 -- Tool versions: Xilinx ISE 9.2i
9 -- Description: This is a ZBT SRAM controller which is Wishbone rev B.3 compatible (classic + burst r/w operations).
11 -- Dependencies: It may be run on any board/FPGA with a ZBT SRAM pin compatible (or at least in the control signals)
12 -- with the one on the ML506 board (ISSI IS61NLP 256kx36 ZBT SRAM)
15 -- LICENSE TERMS: (CCPL) Creative Commons Attribution-Noncommercial-Share Alike 3.0 Unported.
16 -- http://creativecommons.org/licenses/by-nc-sa/3.0/
18 -- That is you may use it only in NON-COMMERCIAL projects.
19 -- You are required to include in the copyrights/about section
20 -- that your system contains a "ZBT SRAM Controller (C) Victor Lopez Lorenzo under CCPL license"
21 -- This holds also in the case where you modify the core, as the resulting core
22 -- would be a derived work.
23 -- Also, we would like to know if you use this core in a project of yours, just an email will do.
25 -- Please take good note of the disclaimer section of the CCPL license, as we don't
26 -- take any responsability for anything that this core does.
27 ----------------------------------------------------------------------------------
31 use IEEE.STD_LOGIC_1164.ALL;
32 use IEEE.STD_LOGIC_ARITH.ALL;
33 use IEEE.STD_LOGIC_UNSIGNED.ALL;
35 -- WB: MASTER MUST NOT insert wait states!
36 -- WB: maximum burst length is 4 (but bursts may follow without wait states in between)
39 Port ( clk : in STD_LOGIC;
42 SRAM_CLK : out STD_LOGIC; --Synchronous Clock (up to 200 MHz)
44 --A burst mode pin (MODE) defines the order of the burst sequence. When tied HIGH, the interleaved burst sequence is selected.
45 --When tied LOW, the linear burst sequence is selected.
46 SRAM_MODE : out STD_LOGIC; --Burst Sequence Selection (pulled down on PCB)
48 SRAM_CS_B : out STD_LOGIC; --Synchronous Chip Enable (CE\, pulled up on PCB)
50 --For write cycles following read cycles, the output buffers must be disabled with OE\, otherwise data bus contention will occur
51 SRAM_OE_B : out STD_LOGIC; --Output Enable (OE\, pulled up on PCB)
53 --Write cycles are internally self-timed and are initiated by the rising edge of the clock inputs and when WE\ is LOW.
54 SRAM_FLASH_WE_B : out STD_LOGIC; --Synchronous Read/Write Control Input (pulled up on PCB)
56 --All Read, Write and Deselect cycles are initiated by the ADV input. When the ADV input is HIGH the internal
57 --burst counter is incremented. New external addresses can be loaded when ADV is LOW.
58 SRAM_ADV_LD_B : out STD_LOGIC; --Synchronous Burst Address Advance/Load (pulled down on PCB)
61 SRAM_BW0 : out STD_LOGIC; --Synchronous Byte Write Enable 0 (active low)
62 SRAM_BW1 : out STD_LOGIC; --Synchronous Byte Write Enable 1 (active low)
63 SRAM_BW2 : out STD_LOGIC; --Synchronous Byte Write Enable 2 (active low)
64 SRAM_BW3 : out STD_LOGIC; --Synchronous Byte Write Enable 3 (active low)
66 --SRAM_FLASH_A0 : out STD_LOGIC; --not connected to SRAM!
67 SRAM_FLASH_A1 : out STD_LOGIC; --Synchronous Address Input 0
68 SRAM_FLASH_A2 : out STD_LOGIC; --Synchronous Address Input 1
69 SRAM_FLASH_A3 : out STD_LOGIC;
70 SRAM_FLASH_A4 : out STD_LOGIC;
71 SRAM_FLASH_A5 : out STD_LOGIC;
72 SRAM_FLASH_A6 : out STD_LOGIC;
73 SRAM_FLASH_A7 : out STD_LOGIC;
74 SRAM_FLASH_A8 : out STD_LOGIC;
75 SRAM_FLASH_A9 : out STD_LOGIC;
76 SRAM_FLASH_A10 : out STD_LOGIC;
77 SRAM_FLASH_A11 : out STD_LOGIC;
78 SRAM_FLASH_A12 : out STD_LOGIC;
79 SRAM_FLASH_A13 : out STD_LOGIC;
80 SRAM_FLASH_A14 : out STD_LOGIC;
81 SRAM_FLASH_A15 : out STD_LOGIC;
82 SRAM_FLASH_A16 : out STD_LOGIC;
83 SRAM_FLASH_A17 : out STD_LOGIC;
84 SRAM_FLASH_A18 : out STD_LOGIC;
86 SRAM_FLASH_D0 : inout STD_LOGIC;
87 SRAM_FLASH_D1 : inout STD_LOGIC;
88 SRAM_FLASH_D2 : inout STD_LOGIC;
89 SRAM_FLASH_D3 : inout STD_LOGIC;
90 SRAM_FLASH_D4 : inout STD_LOGIC;
91 SRAM_FLASH_D5 : inout STD_LOGIC;
92 SRAM_FLASH_D6 : inout STD_LOGIC;
93 SRAM_FLASH_D7 : inout STD_LOGIC;
94 SRAM_FLASH_D8 : inout STD_LOGIC;
95 SRAM_FLASH_D9 : inout STD_LOGIC;
96 SRAM_FLASH_D10 : inout STD_LOGIC;
97 SRAM_FLASH_D11 : inout STD_LOGIC;
98 SRAM_FLASH_D12 : inout STD_LOGIC;
99 SRAM_FLASH_D13 : inout STD_LOGIC;
100 SRAM_FLASH_D14 : inout STD_LOGIC;
101 SRAM_FLASH_D15 : inout STD_LOGIC;
102 SRAM_D16 : inout STD_LOGIC;
103 SRAM_D17 : inout STD_LOGIC;
104 SRAM_D18 : inout STD_LOGIC;
105 SRAM_D19 : inout STD_LOGIC;
106 SRAM_D20 : inout STD_LOGIC;
107 SRAM_D21 : inout STD_LOGIC;
108 SRAM_D22 : inout STD_LOGIC;
109 SRAM_D23 : inout STD_LOGIC;
110 SRAM_D24 : inout STD_LOGIC;
111 SRAM_D25 : inout STD_LOGIC;
112 SRAM_D26 : inout STD_LOGIC;
113 SRAM_D27 : inout STD_LOGIC;
114 SRAM_D28 : inout STD_LOGIC;
115 SRAM_D29 : inout STD_LOGIC;
116 SRAM_D30 : inout STD_LOGIC;
117 SRAM_D31 : inout STD_LOGIC;
119 SRAM_DQP0 : inout STD_LOGIC; --Parity Data I/O 0
120 SRAM_DQP1 : inout STD_LOGIC; --Parity Data I/O 1
121 SRAM_DQP2 : inout STD_LOGIC; --Parity Data I/O 2
122 SRAM_DQP3 : inout STD_LOGIC; --Parity Data I/O 3
126 wb_adr_i : in std_logic_vector(17 downto 0);
127 wb_we_i : in std_logic;
128 wb_dat_i : in std_logic_vector(35 downto 0);
129 wb_sel_i : in std_logic_vector(3 downto 0);
130 wb_dat_o : out std_logic_vector(35 downto 0);
131 wb_cyc_i : in std_logic;
132 wb_stb_i : in std_logic;
133 wb_cti_i : in std_logic_vector(2 downto 0);
134 wb_bte_i : in std_logic_vector(1 downto 0);
135 wb_ack_o : out std_logic;
136 wb_err_o : out std_logic;
137 wb_tga_i: in std_logic := '0' --'0' to mean last (or single) 4 words burst
142 architecture Behavioral of zbt_top is
143 signal ZBT_addr, ZBT_addr2 : std_logic_vector(17 downto 0);
144 signal ZBT_din, ZBT_din2, ZBT_din1 : std_logic_vector(35 downto 0);
145 signal ZBT_dout : std_logic_vector(35 downto 0);
146 signal BW_enable, SRAM_OE_B2 : std_logic;
148 signal State : integer;
150 constant IDLE : integer := 0;
151 constant C1 : integer := 1;
152 constant C2 : integer := 2;
153 constant C3 : integer := 3;
154 constant C4 : integer := 4;
155 constant B1 : integer := 5;
156 constant B2 : integer := 6;
157 constant B3 : integer := 7;
158 constant B4 : integer := 8;
159 constant B5 : integer := 9;
160 constant B6 : integer := 10;
161 constant B4L : integer := 11;
162 constant B5L : integer := 12;
163 constant B6L : integer := 13;
164 constant B0W : integer := 14;
165 constant B1W : integer := 15;
166 constant B2W : integer := 16;
167 constant B3W : integer := 17;
168 constant B4WL : integer := 18;
169 constant B5WL : integer := 19;
172 FSM_State_Control : process (clk, reset)
174 if (reset = '1') then
176 elsif (clk = '1' and clk'event) then
179 if (wb_cyc_i = '1' and wb_stb_i = '1') then --start of WB cycle?
180 if (wb_bte_i /= "00" or wb_cti_i /= "010") then --classic cycle
181 --(WB rule 4.25, only linear bursts accepted, WB permission 4.40: EOB=single access~=sync.classic cycle, WB rule 4.10: unknown=classic cycles)
182 --we were in idle state, so any classic cycle, EOB cycle or any cycle with a non linear burst is executed as a classic one
184 else --Incrementing burst cycle with linear burst type
185 assert (wb_bte_i = "00" and wb_cti_i="010") report "Bad else on IDLE state (cti=" & integer'image(conv_integer(wb_cti_i)) & ", bte=" & integer'image(conv_integer(wb_bte_i)) & ")" severity FAILURE;
186 if (wb_we_i = '0') then --wb burst read?
188 else --wb burst write?
196 --start single word read/write
198 if (wb_cyc_i = '1' and wb_stb_i = '1') then State <= C2; else State <= IDLE; end if;
199 when C2 => --wb_ack <= '1' in this cycle
200 if (wb_cyc_i = '1' and wb_stb_i = '1') then State <= C3; else State <= IDLE; end if;
201 when C3 => --wb_ack = '1' in this cycle
209 if (wb_cyc_i = '1' and wb_stb_i = '1' and wb_cti_i /= "111") then State <= B2; else State <= IDLE; end if;
211 if (wb_cyc_i = '1' and wb_stb_i = '1' and wb_cti_i /= "111") then State <= B3; else State <= IDLE; end if;
213 if (wb_cyc_i = '1' and wb_stb_i = '1' and wb_cti_i /= "111") then
214 if (wb_tga_i = '0') then --last burst?
223 if (wb_cyc_i = '1' and wb_stb_i = '1' and wb_cti_i /= "111") then State <= B5; else State <= IDLE; end if;
225 if (wb_cyc_i = '1' and wb_stb_i = '1' and wb_cti_i /= "111") then State <= B6; else State <= IDLE; end if;
226 when B6 => --go back to B3
227 if (wb_cyc_i = '1' and wb_stb_i = '1' and wb_cti_i /= "111") then State <= B3; else State <= IDLE; end if;
230 if (wb_cyc_i = '1' and wb_stb_i = '1' and wb_cti_i /= "111") then State <= B5L; else State <= IDLE; end if;
232 if (wb_cyc_i = '1' and wb_stb_i = '1' and wb_cti_i /= "111") then State <= B6L; else State <= IDLE; end if;
233 when B6L => --in this cycle wb_cti_i must be 111 because the ZBT has a burst length of 4
238 if (wb_cyc_i = '1' and wb_stb_i = '1' and wb_cti_i /= "111") then State <= B1W; else State <= IDLE; end if;
240 if (wb_cyc_i = '1' and wb_stb_i = '1' and wb_cti_i /= "111") then State <= B2W; else State <= IDLE; end if;
242 if (wb_cyc_i = '1' and wb_stb_i = '1' and wb_cti_i /= "111") then State <= B3W; else State <= IDLE; end if;
244 if (wb_cyc_i = '1' and wb_stb_i = '1') then --wb_cti should be "111" if it is the last burst
245 if (wb_tga_i = '0') then --last burst?
255 when B4WL => --don't check cti as it was 111 in B3W for the last burst!
261 report "Bad state on FSM_State_Control " & integer'image(State) severity FAILURE;
264 end process FSM_State_Control;
268 Wishbone_Slave_Control : process (clk, reset)
270 if (reset = '1') then
273 elsif (clk = '1' and clk'event) then
277 if (wb_cyc_i='1' and wb_stb_i='1' and wb_we_i='1' and wb_bte_i="00" and wb_cti_i="010") then --burst write cycle?
278 wb_ack_o <= '1'; --preack the master to have it give us the next wb_sel_i and wb_dat_i signals
283 when C1 | C3 | C4 | B1 | B6L | B4WL | B5WL => --in the case of bursts cyc MUST be lowered after cti="111"
284 wb_ack_o <= '0'; --in the case of classic cycles, we have C3 and C4 where ack is lowered, to make the master lower cyc
286 when C2 | B2 | B3 | B4 | B5 | B6 | B4L | B5L | B0W | B1W | B2W =>
287 wb_ack_o <= wb_cyc_i and wb_stb_i; --ack should be 1, but it will only go up if cyc and stb are so
289 when B3W => --last write burst?
290 wb_ack_o <= wb_tga_i and wb_cyc_i and wb_stb_i; --ack should be 1, but it will only go up if cyc and stb are so (and if it is not the last burst)
293 report "Bad state on WB_Slave_Control " & integer'image(State) severity FAILURE;
296 end process Wishbone_Slave_Control;
298 wb_dat_o <= ZBT_dout;
300 ZBT_SRAM_Control : process (clk, reset)
301 variable vBW_enable : std_logic;
303 if (reset = '1') then
304 SRAM_ADV_LD_B <= '0';
305 SRAM_CS_B <= '1'; --chip NOT selected
306 SRAM_FLASH_WE_B <= '1'; --DON'T write anything
308 --by default output is not enabled to avoid bus contemption with the wb master
309 SRAM_OE_B2 <= '1'; --output NOT enabled
311 ZBT_addr <= (others => '0');
312 ZBT_addr2 <= (others => '0');
314 ZBT_din2 <= (others => '0');
315 ZBT_din1 <= (others => '0');
316 ZBT_din <= (others => '0');
324 elsif (clk = '1' and clk'event) then
325 --two stage datain pipeline
326 ZBT_din2 <= wb_dat_i;
327 ZBT_din1 <= ZBT_din2;
330 --REASON WHY THERE IS A DATAIN PIPELINE:
331 --Based on the ZBT SRAM datasheet:
332 --it doesn't make much sense but the "byte write enables" are not fed to the ZBT
333 --at the same time than the data to be written, so the wb_sel_i lines arrive late
334 --(because they arrive, obviously, at the same time than their associated wb_dat_i lines)
335 --which is 2 cycles later than when they should be fed to the ZBT
336 --the only solution is, on wb writes:
337 -- 1) start wb_acking soon (to have the master give us soon enough the right wb_sel lines for each data word to write)
338 -- 2) make two registers to have a two stage pipeline for the data words in order to feed them to the ZBT at the 3rd cycle
339 -- this means 72 extra FFs for the registers and a more complex wb slave logic (differentiate if read or write)
340 -- there would be the same number of acks but the 2 cycles response latency would happen at the end of the last burst of the wb write
343 when IDLE => --prepare signals for next cycle
345 SRAM_ADV_LD_B <= '0';
346 if (wb_cyc_i = '1' and wb_stb_i = '1') then
347 ZBT_addr <= wb_adr_i;
348 ZBT_addr2 <= wb_adr_i + x"4";
349 if (wb_bte_i /= "00" or wb_cti_i /= "010") then --classic cycle?
350 SRAM_CS_B <= '0'; --chip selected
351 SRAM_OE_B2 <= wb_we_i; --if it's a read -> enable outputs
352 SRAM_FLASH_WE_B <= not wb_we_i;
353 vBW_enable := wb_we_i;
355 if (wb_we_i = '0') then --wb burst read?
356 SRAM_CS_B <= '0'; --chip selected
357 SRAM_OE_B2 <= wb_we_i; --if it's a read -> enable outputs
358 SRAM_FLASH_WE_B <= not wb_we_i;
359 else --wb burst write? start ZBT in B0W but get now ZBT_addr2!
360 ZBT_addr2 <= wb_adr_i; --important because ZBT_addr2 will be assigned in next cycle (so don't sum 4 to it)
361 SRAM_CS_B <= '1'; --chip NOT selected
362 SRAM_OE_B2 <= '1'; --output NOT enabled for next cycle
363 SRAM_FLASH_WE_B <= '1'; --DON'T write anything
367 SRAM_CS_B <= '1'; --chip NOT selected
368 SRAM_OE_B2 <= '1'; --output NOT enabled for next cycle
369 SRAM_FLASH_WE_B <= '1'; --DON'T write anything
370 ZBT_addr <= (others => '0');
371 ZBT_addr2 <= (others => '0');
376 SRAM_CS_B <= '1'; --chip NOT selected (doesn't affect current op.: don't care in datasheet)
377 SRAM_ADV_LD_B <= '0'; --NOT a burst
378 --SRAM_OE_B2 keep the selected output enable for the current WB operation
379 vBW_enable := '0'; --it only matters for the ADV=0 cycle of the ZBT operation
382 SRAM_CS_B <= '1'; --chip NOT selected (doesn't affect current op.: don't care in datasheet)
383 SRAM_ADV_LD_B <= '0'; --NOT a burst
384 SRAM_OE_B2 <= '1'; --output NOT enabled for next cycle
389 when B1 | B2 | B3 | B5 | B6 =>
390 SRAM_ADV_LD_B <= '1';
392 when B4 => --precharge address for next 4 word burst
393 SRAM_ADV_LD_B <= '0';
394 ZBT_addr <= ZBT_addr2;
395 ZBT_addr2 <= ZBT_addr2 + x"4";
397 when B4L | B5L | B6L => --last burst
398 SRAM_ADV_LD_B <= '0';
399 SRAM_CS_B <= '1'; --chip NOT selected
402 when B0W => --a wb write starts here
403 SRAM_ADV_LD_B <= '0'; --first write cycle
404 SRAM_OE_B2 <= '1'; --keep output NOT enabled (it's a write)
405 SRAM_CS_B <= '0'; --chip selected
406 SRAM_FLASH_WE_B <= '0'; --start writing
407 ZBT_addr <= ZBT_addr2;
408 ZBT_addr2 <= ZBT_addr2 + x"4";
411 when B1W | B2W | B3W =>
412 SRAM_ADV_LD_B <= '1';
416 SRAM_CS_B <= '1'; --chip NOT selected (don't care in datasheet)
417 SRAM_FLASH_WE_B <= '1'; --DON'T write (don't care in datasheet)
418 SRAM_ADV_LD_B <= '0';
422 report "Bad state on ZBT_SRAM_Control " & integer'image(State) severity FAILURE;
425 BW_enable <= vBW_enable;
426 --Byte write enables are active low
427 SRAM_BW0 <= not (wb_sel_i(0) and vBW_enable);
428 SRAM_BW1 <= not (wb_sel_i(1) and vBW_enable);
429 SRAM_BW2 <= not (wb_sel_i(2) and vBW_enable);
430 SRAM_BW3 <= not (wb_sel_i(3) and vBW_enable);
432 end process ZBT_SRAM_Control;
437 SRAM_MODE <= '0'; --linear bursts
438 SRAM_OE_B <= SRAM_OE_B2; --to let OE_B2 be read to mux the data lines
441 ---------------------------------
443 ---------------------------------
444 SRAM_FLASH_D0 <= ZBT_din(0) when (SRAM_OE_B2 = '1') else 'Z';
445 SRAM_FLASH_D1 <= ZBT_din(1) when (SRAM_OE_B2 = '1') else 'Z';
446 SRAM_FLASH_D2 <= ZBT_din(2) when (SRAM_OE_B2 = '1') else 'Z';
447 SRAM_FLASH_D3 <= ZBT_din(3) when (SRAM_OE_B2 = '1') else 'Z';
448 SRAM_FLASH_D4 <= ZBT_din(4) when (SRAM_OE_B2 = '1') else 'Z';
449 SRAM_FLASH_D5 <= ZBT_din(5) when (SRAM_OE_B2 = '1') else 'Z';
450 SRAM_FLASH_D6 <= ZBT_din(6) when (SRAM_OE_B2 = '1') else 'Z';
451 SRAM_FLASH_D7 <= ZBT_din(7) when (SRAM_OE_B2 = '1') else 'Z';
452 SRAM_FLASH_D8 <= ZBT_din(8) when (SRAM_OE_B2 = '1') else 'Z';
453 SRAM_FLASH_D9 <= ZBT_din(9) when (SRAM_OE_B2 = '1') else 'Z';
454 SRAM_FLASH_D10 <= ZBT_din(10) when (SRAM_OE_B2 = '1') else 'Z';
455 SRAM_FLASH_D11 <= ZBT_din(11) when (SRAM_OE_B2 = '1') else 'Z';
456 SRAM_FLASH_D12 <= ZBT_din(12) when (SRAM_OE_B2 = '1') else 'Z';
457 SRAM_FLASH_D13 <= ZBT_din(13) when (SRAM_OE_B2 = '1') else 'Z';
458 SRAM_FLASH_D14 <= ZBT_din(14) when (SRAM_OE_B2 = '1') else 'Z';
459 SRAM_FLASH_D15 <= ZBT_din(15) when (SRAM_OE_B2 = '1') else 'Z';
460 SRAM_D16 <= ZBT_din(16) when (SRAM_OE_B2 = '1') else 'Z';
461 SRAM_D17 <= ZBT_din(17) when (SRAM_OE_B2 = '1') else 'Z';
462 SRAM_D18 <= ZBT_din(18) when (SRAM_OE_B2 = '1') else 'Z';
463 SRAM_D19 <= ZBT_din(19) when (SRAM_OE_B2 = '1') else 'Z';
464 SRAM_D20 <= ZBT_din(20) when (SRAM_OE_B2 = '1') else 'Z';
465 SRAM_D21 <= ZBT_din(21) when (SRAM_OE_B2 = '1') else 'Z';
466 SRAM_D22 <= ZBT_din(22) when (SRAM_OE_B2 = '1') else 'Z';
467 SRAM_D23 <= ZBT_din(23) when (SRAM_OE_B2 = '1') else 'Z';
468 SRAM_D24 <= ZBT_din(24) when (SRAM_OE_B2 = '1') else 'Z';
469 SRAM_D25 <= ZBT_din(25) when (SRAM_OE_B2 = '1') else 'Z';
470 SRAM_D26 <= ZBT_din(26) when (SRAM_OE_B2 = '1') else 'Z';
471 SRAM_D27 <= ZBT_din(27) when (SRAM_OE_B2 = '1') else 'Z';
472 SRAM_D28 <= ZBT_din(28) when (SRAM_OE_B2 = '1') else 'Z';
473 SRAM_D29 <= ZBT_din(29) when (SRAM_OE_B2 = '1') else 'Z';
474 SRAM_D30 <= ZBT_din(30) when (SRAM_OE_B2 = '1') else 'Z';
475 SRAM_D31 <= ZBT_din(31) when (SRAM_OE_B2 = '1') else 'Z';
476 SRAM_DQP0 <= ZBT_din(32) when (SRAM_OE_B2 = '1') else 'Z';
477 SRAM_DQP1 <= ZBT_din(33) when (SRAM_OE_B2 = '1') else 'Z';
478 SRAM_DQP2 <= ZBT_din(34) when (SRAM_OE_B2 = '1') else 'Z';
479 SRAM_DQP3 <= ZBT_din(35) when (SRAM_OE_B2 = '1') else 'Z';
482 ---------------------------------
484 ---------------------------------
485 ZBT_dout(0) <= SRAM_FLASH_D0;
486 ZBT_dout(1) <= SRAM_FLASH_D1;
487 ZBT_dout(2) <= SRAM_FLASH_D2;
488 ZBT_dout(3) <= SRAM_FLASH_D3;
489 ZBT_dout(4) <= SRAM_FLASH_D4;
490 ZBT_dout(5) <= SRAM_FLASH_D5;
491 ZBT_dout(6) <= SRAM_FLASH_D6;
492 ZBT_dout(7) <= SRAM_FLASH_D7;
493 ZBT_dout(8) <= SRAM_FLASH_D8;
494 ZBT_dout(9) <= SRAM_FLASH_D9;
495 ZBT_dout(10) <= SRAM_FLASH_D10;
496 ZBT_dout(11) <= SRAM_FLASH_D11;
497 ZBT_dout(12) <= SRAM_FLASH_D12;
498 ZBT_dout(13) <= SRAM_FLASH_D13;
499 ZBT_dout(14) <= SRAM_FLASH_D14;
500 ZBT_dout(15) <= SRAM_FLASH_D15;
501 ZBT_dout(16) <= SRAM_D16;
502 ZBT_dout(17) <= SRAM_D17;
503 ZBT_dout(18) <= SRAM_D18;
504 ZBT_dout(19) <= SRAM_D19;
505 ZBT_dout(20) <= SRAM_D20;
506 ZBT_dout(21) <= SRAM_D21;
507 ZBT_dout(22) <= SRAM_D22;
508 ZBT_dout(23) <= SRAM_D23;
509 ZBT_dout(24) <= SRAM_D24;
510 ZBT_dout(25) <= SRAM_D25;
511 ZBT_dout(26) <= SRAM_D26;
512 ZBT_dout(27) <= SRAM_D27;
513 ZBT_dout(28) <= SRAM_D28;
514 ZBT_dout(29) <= SRAM_D29;
515 ZBT_dout(30) <= SRAM_D30;
516 ZBT_dout(31) <= SRAM_D31;
517 ZBT_dout(32) <= SRAM_DQP0;
518 ZBT_dout(33) <= SRAM_DQP1;
519 ZBT_dout(34) <= SRAM_DQP2;
520 ZBT_dout(35) <= SRAM_DQP3;
523 ---------------------------------
525 ---------------------------------
526 SRAM_FLASH_A1 <= ZBT_addr(0);
527 SRAM_FLASH_A2 <= ZBT_addr(1);
528 SRAM_FLASH_A3 <= ZBT_addr(2);
529 SRAM_FLASH_A4 <= ZBT_addr(3);
530 SRAM_FLASH_A5 <= ZBT_addr(4);
531 SRAM_FLASH_A6 <= ZBT_addr(5);
532 SRAM_FLASH_A7 <= ZBT_addr(6);
533 SRAM_FLASH_A8 <= ZBT_addr(7);
534 SRAM_FLASH_A9 <= ZBT_addr(8);
535 SRAM_FLASH_A10 <= ZBT_addr(9);
536 SRAM_FLASH_A11 <= ZBT_addr(10);
537 SRAM_FLASH_A12 <= ZBT_addr(11);
538 SRAM_FLASH_A13 <= ZBT_addr(12);
539 SRAM_FLASH_A14 <= ZBT_addr(13);
540 SRAM_FLASH_A15 <= ZBT_addr(14);
541 SRAM_FLASH_A16 <= ZBT_addr(15);
542 SRAM_FLASH_A17 <= ZBT_addr(16);
543 SRAM_FLASH_A18 <= ZBT_addr(17);