?? ddr_sdram_example_driver.v
字號:
begin
if (wdata_req)
writes_remaining <= writes_remaining + (size - 1);
else
writes_remaining <= writes_remaining + size;
end
else if ((wdata_req) && (writes_remaining > 0))
//size
writes_remaining <= writes_remaining - 1'b1;
else
writes_remaining <= writes_remaining;
if (read_req && local_ready)
begin
if (local_rdata_valid)
reads_remaining <= reads_remaining + (size - 1);
else
reads_remaining <= reads_remaining + size;
end
else if ((local_rdata_valid) && (reads_remaining > 0))
reads_remaining <= reads_remaining - 1'b1;
else
reads_remaining <= reads_remaining;
case (state)
4'd0: begin
reached_max_count <= 0;
if (avalon_burst_mode == 0)
begin
if (1 == 0)
state <= 5;
else
state <= 1;
end
else
begin
burst_begin <= 1;
write_req <= 1'b1;
state <= 10;
end
dgen_enable <= 1'b1;
//Reset just in case!
writes_remaining <= 0;
reads_remaining <= 0;
end // 4'd0
4'd1: begin
write_req <= 1'b1;
dgen_enable <= 1'b1;
if (local_ready && write_req)
if (reached_max_count)
begin
state <= 2;
write_req <= 1'b0;
reset_address <= 1'b1;
end
end // 4'd1
4'd10: begin
reset_address <= 1'b0;
write_req <= 1'b1;
burst_begin <= 0;
if (local_ready)
begin
burst_beat_count <= burst_beat_count + 1;
state <= 12;
end
end // 4'd10
4'd11: begin
reset_address <= 1'b0;
read_req <= 1'b1;
if (! local_ready)
begin
burst_begin <= 0;
state <= 13;
end
if (avalon_read_burst_max_address)
begin
read_req <= 1'b0;
reset_address <= 1'b1;
test_complete <= 1'b1;
burst_beat_count <= 0;
state <= 4;
end
end // 4'd11
4'd12: begin
write_req <= 1'b1;
if (local_ready)
if (burst_beat_count == size - 1)
begin
if (reached_max_count)
begin
write_req <= 1'b0;
burst_beat_count <= 0;
reset_address <= 1'b1;
dgen_enable <= 1'b0;
state <= 2;
end
else
begin
burst_begin <= 1;
write_req <= 1'b1;
burst_beat_count <= 0;
state <= 10;
end
end
else
burst_beat_count <= burst_beat_count + 1;
end // 4'd12
4'd13: begin
read_req <= 1'b1;
if (local_ready)
begin
burst_begin <= 1;
read_req <= 1'b1;
state <= 11;
end
else if (avalon_read_burst_max_address)
begin
read_req <= 1'b0;
reset_address <= 1'b1;
test_complete <= 1'b1;
dgen_enable <= 1'b0;
state <= 4;
end
end // 4'd13
4'd2: begin
if (avalon_burst_mode == 0)
begin
if (writes_remaining == 0)
begin
state <= 3;
dgen_enable <= 1'b0;
end
end
else
begin
dgen_enable <= 1'b1;
burst_begin <= 1;
read_req <= 1'b1;
reset_address <= 1'b0;
state <= 11;
end
end // 4'd2
4'd3: begin
read_req <= 1'b1;
dgen_enable <= 1'b1;
if (local_ready && read_req)
if (reached_max_count)
begin
state <= 4;
read_req <= 1'b0;
reset_address <= 1'b1;
end
end // 4'd3
4'd4: begin
if (avalon_burst_mode == 0)
begin
if (reads_remaining == 0)
begin
state <= 0;
dgen_enable <= 1'b0;
test_complete <= 1'b1;
end
end
else
begin
if (reads_remaining == 1)
dgen_enable <= 1'b0;
if (reads_remaining == 0)
begin
dgen_enable <= 1'b1;
burst_begin <= 1;
write_req <= 1'b1;
read_req <= 1'b0;
reset_address <= 1'b0;
burst_beat_count <= 0;
state <= 10;
end
end
end // 4'd4
4'd5: begin
write_req <= 1'b1;
dgen_enable <= 1'b1;
wait_first_write_data <= 1'b1;
if (local_ready)
begin
state <= 6;
write_req <= 1'b0;
end
end // 4'd5
4'd6: begin
if (writes_remaining == 0)
begin
state <= 7;
dgen_load <= 1'b1;
end
end // 4'd6
4'd7: begin
read_req <= 1'b1;
dgen_enable <= 1'b1;
if (local_ready)
begin
state <= 8;
read_req <= 1'b0;
end
end // 4'd7
4'd8: begin
if (reads_remaining == 0)
if (1)
begin
reset_address <= 1'b1;
dgen_enable <= 1'b0;
state <= 0;
test_complete <= 1'b1;
end
else
state <= 5;
end // 4'd8
endcase // state
if (reset_address)
begin
//(others => '0')
cs_addr <= MIN_CHIPSEL;
row_addr <= 0;
bank_addr <= 0;
col_addr <= 0;
end
else if ((((local_ready && write_req) && (state == 1))) || ((local_ready && read_req) && (state == 3)) || ((local_ready) && ((state == 7) || (state == 10) || (state == 11) || (state == 13))))
if (col_addr >= MAX_COL)
begin
col_addr <= 0;
if (row_addr == MAX_ROW)
begin
row_addr <= 0;
if (bank_addr == MAX_BANK)
begin
bank_addr <= 0;
if (cs_addr == MAX_CHIPSEL)
//reached_max_count <= TRUE
//(others => '0')
cs_addr <= MIN_CHIPSEL;
else
cs_addr <= cs_addr + 1'b1;
end
else
bank_addr <= bank_addr + 1'b1;
end
else
row_addr <= row_addr + 1'b1;
end
else
col_addr <= col_addr + (1 * 2);
end
end
//------------------------------------------------------------
//LFSR re-load data storage
//Comparator masking and test pass signal generation
//------------------------------------------------------------
always @(posedge clk or negedge reset_n)
begin
if (reset_n == 0)
begin
dgen_ldata <= 0;
last_wdata_req <= 1'b0;
//all ones
compare_valid <= -1;
//all ones
compare_valid_reg <= -1;
pnf_persist <= 1'b1;
pnf_persist1 <= 1'b1;
//all ones
compare_reg <= -1;
last_rdata_valid <= 1'b0;
end
else
begin
last_wdata_req <= wdata_req;
last_rdata_valid <= local_rdata_valid;
compare_reg <= compare;
if (wdata_req)
//Store the data from the first write in a burst
//Used to reload the lfsr for the first read in a burst in WRITE 1, READ 1 mode
if (wait_first_write_data)
dgen_ldata <= dgen_data;
//Enable the comparator result when read data is valid
if (last_rdata_valid)
compare_valid <= compare_reg;
//Create the overall persistent passnotfail output
if (~&compare_valid)
pnf_persist1 <= 1'b0;
//Extra register stage to help Tco / Fmax on comparator output pins
compare_valid_reg <= compare_valid;
pnf_persist <= pnf_persist1;
end
end
endmodule
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