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URL https://opencores.org/ocsvn/sdram_controller/sdram_controller/trunk

Subversion Repositories sdram_controller

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  • This comparison shows the changes necessary to convert path 
    /sdram_controller
    from Rev 16 to Rev 17
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Rev 16 → Rev 17

/trunk/sdram.vhd
233,7 → 233,7
-- various wait counter values
constant AUTO_REFRESH_CLKS : integer := 700; -- spec says 7.8us, which is 780 clocks @ 100Mhz, I'm setting it to 700
constant WRITE_RECOVER_CLKS : integer := 5; -- these are fudged a bit, you *might* be able to shave a clock or two off
constant READ_DONE_CLKS : integer := 5;
constant READ_DONE_CLKS : integer := 4; -- or shave a clock or two off if your board timing is a bit wedgy
 
type CMD_STATES is ( STATE_START, STATE_INIT, STATE_WAIT_INIT, STATE_IDLE, STATE_IDLE_AUTO_REFRESH,
STATE_IDLE_CHECK_OP_PENDING, STATE_IDLE_WAIT_AR_CTR, STATE_IDLE_WAIT_AUTO_REFRESH,
458,18 → 458,26
dram_cs <= '0';
data_o <= data1_o when addr_save(0) = '1' else data0_o;
-- process (clk_000)
-- begin
-- if (cap_en = '1') then
-- if (rising_edge(clk_000)) then
-- addr_save <= addr;
-- datai_save <= data_i;
-- op_save <= op;
-- end if;
-- end if;
-- end process;
 
-- this will probably make the synthesizer scream bloody murder
-- over either a transparent latch or gated clock or both
-- but i've got it working again with my SoC and I'll see about
-- changing it back to something less icky later
-- capture addr, data_i and op for the cmd fsm
-- op needs to be captured during AR or it might get dropped
process (clk_000)
begin
if (rising_edge(clk_000)) then
if (cap_en = '1') then
addr_save <= addr;
datai_save <= data_i;
op_save <= op;
end if;
end if;
end process;
addr_save <= addr when cap_en = '1' else addr_save;
datai_save <= data_i when cap_en = '1' else datai_save;
op_save <= op when cap_en = '1' else op_save;
-- command state machine
process (clk_000)
515,11 → 523,13
cmd_state <= STATE_IDLE_AUTO_REFRESH;
elsif (op = "01") then
busy_n <= '0';
op_ack <= '1';
op_ack <= '1';
cap_en <= '0';
cmd_state <= STATE_READ_ROW_OPEN;
elsif (op = "10") then
busy_n <= '0';
op_ack <= '1';
cap_en <= '0';
cmd_state <= STATE_WRITE_ROW_OPEN;
else
cmd_state <= cmd_state;
559,19 → 569,22
cmd_state <= cmd_state;
end if;
when STATE_IDLE_CHECK_OP_PENDING =>
if (op_save = "01") then
op_ack <= '1';
cmd_state <= STATE_READ_ROW_OPEN;
elsif (op_save = "10") then
op_ack <= '1';
cmd_state <= STATE_WRITE_ROW_OPEN;
when STATE_IDLE_CHECK_OP_PENDING =>
if ( cap_en = '0') then
if (op_save = "01") then
op_ack <= '1';
cmd_state <= STATE_READ_ROW_OPEN;
elsif (op_save = "10") then
op_ack <= '1';
cmd_state <= STATE_WRITE_ROW_OPEN;
else
cmd_state <= STATE_IDLE;
end if;
else
cmd_state <= STATE_IDLE;
end if;
when STATE_WRITE_ROW_OPEN =>
cap_en <= '0';
when STATE_WRITE_ROW_OPEN =>
dqs_dir <= '1';
dq_dir <= '1';
main_cmd <= CMD_ACTIVE;
604,8 → 617,7
cmd_state <= cmd_state;
end if;
when STATE_READ_ROW_OPEN =>
cap_en <= '0';
when STATE_READ_ROW_OPEN =>
dqs_dir <= '0';
dq_dir <= '0';
main_cmd <= CMD_ACTIVE;

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