?? ddr2.v
字號:
end
end
READ : begin
if (!dll_locked)
$display ("%m: at time %t WARNING: %s prior to DLL locked. Failing to wait for synchronization to occur may result in a violation of the tAC or tDQSCK parameters.", $time, cmd_string[cmd]);
if (!init_done) begin
$display ("%m: at time %t ERROR: %s Failure. Initialization sequence is not complete.", $time, cmd_string[cmd]);
if (STOP_ON_ERROR) $stop(0);
end else if (!active_bank[bank]) begin
$display ("%m: at time %t ERROR: %s Failure. Bank %d must be Activated.", $time, cmd_string[cmd], bank);
if (STOP_ON_ERROR) $stop(0);
end else if (auto_precharge_bank[bank]) begin
$display ("%m: at time %t ERROR: %s Failure. Auto Precharge is scheduled to bank %d.", $time, cmd_string[cmd], bank);
if (STOP_ON_ERROR) $stop(0);
end else if ((ck_cntr - ck_read < burst_length/2) && (ck_cntr - ck_read)%2) begin
$display ("%m: at time %t ERROR: %s Failure. Illegal burst interruption.", $time, cmd_string[cmd]);
if (STOP_ON_ERROR) $stop(0);
end else begin
if (addr[AP]) begin
auto_precharge_bank[bank] = 1'b1;
read_precharge_bank[bank] = 1'b1;
end
col = ((addr>>1) & -1*(1<<AP)) | (addr & {AP{1'b1}});
if (col >= 1<<COL_BITS) begin
$display ("%m: at time %t WARNING: col = %h does not exist. Maximum col = %h", $time, col, (1<<COL_BITS)-1);
end
if (DEBUG) $display ("%m: at time %t INFO: %s bank %d col %h, auto precharge %d", $time, cmd_string[cmd], bank, col, addr[AP]);
rd_pipeline[2*read_latency - 1] = 1;
ba_pipeline[2*read_latency - 1] = bank;
row_pipeline[2*read_latency - 1] = active_row[bank];
col_pipeline[2*read_latency - 1] = col;
ck_bank_read[bank] <= ck_cntr;
ck_read <= ck_cntr;
end
end
NOP: begin
if (in_power_down) begin
if (DEBUG) $display ("%m: at time %t INFO: Power Down Exit", $time);
in_power_down = 0;
if (|active_bank & low_power) begin // slow exit active power down
ck_slow_exit_pd <= ck_cntr;
end
ck_power_down <= ck_cntr;
end
if (in_self_refresh) begin
if ($time - tm_cke < TISXR)
$display ("%m: at time %t ERROR: tISXR violation during Self Refresh Exit", $time);
if (DEBUG) $display ("%m: at time %t INFO: Self Refresh Exit", $time);
in_self_refresh = 0;
ck_dll_reset <= ck_cntr;
ck_self_refresh <= ck_cntr;
tm_self_refresh <= $time;
tm_refresh <= $time;
end
end
endcase
if ((prev_cke !== 1) && (cmd !== NOP)) begin
$display ("%m: at time %t ERROR: NOP or Deselect is required when CKE goes active.", $time);
end
if (!init_done) begin
case (init_step)
0 : begin
if ($time < 200000000)
$display ("%m at time %t WARNING: 200 us is required before CKE goes active.", $time);
// if (cmd_chk + 200000000 > $time)
// $display("%m: at time %t WARNING: NOP or DESELECT is required for 200 us before CKE is brought high", $time);
init_step = init_step + 1;
end
1 : if (dll_en) init_step = init_step + 1;
2 : begin
if (&init_mode_reg && dll_reset) begin
active_bank = {`BANKS{1'b1}}; // require Precharge All or bank Precharges
ref_cntr = 0; // require refresh
init_step = init_step + 1;
end
end
3 : if (ref_cntr == 2) begin
init_step = init_step + 1;
end
4 : if (!dll_reset) init_step = init_step + 1;
5 : if (ocd == 3'b111) init_step = init_step + 1;
6 : begin
if (ocd == 3'b000) begin
if (DEBUG) $display ("%m: at time %t INFO: Initialization Sequence is complete", $time);
init_done = 1;
end
end
endcase
end
end else if (prev_cke) begin
if ((!init_done) && (init_step > 1)) begin
$display ("%m: at time %t ERROR: CKE must remain active until the initialization sequence is complete.", $time);
if (STOP_ON_ERROR) $stop(0);
end
case (cmd)
REFRESH : begin
for (j=0; j<NOP; j=j+1) begin
chk_err(1'b0, bank, j, SELF_REF);
end
chk_err(1'b0, bank, PWR_DOWN, SELF_REF);
chk_err(1'b0, bank, SELF_REF, SELF_REF);
if (|active_bank) begin
$display ("%m: at time %t ERROR: Self Refresh Failure. All banks must be Precharged.", $time);
if (STOP_ON_ERROR) $stop(0);
init_done = 0;
end else if (odt_en && odt_state) begin
$display ("%m: at time %t ERROR: ODT must be off prior to entering Self Refresh", $time);
if (STOP_ON_ERROR) $stop(0);
init_done = 0;
end else if (init_done) begin
if (DEBUG) $display ("%m: at time %t INFO: Self Refresh Enter", $time);
in_self_refresh = 1;
dll_locked = 0;
end
end
NOP : begin
// entering slow_exit or precharge power down and tANPD has not been satisfied
if ((low_power || (active_bank == 0)) && (ck_cntr - ck_odt < TANPD))
$display ("%m: at time %t WARNING: tANPD violation during %s. Synchronous or asynchronous change in termination resistance is possible.", $time, cmd_string[PWR_DOWN]);
for (j=0; j<NOP; j=j+1) begin
chk_err(1'b0, bank, j, PWR_DOWN);
end
chk_err(1'b0, bank, PWR_DOWN, PWR_DOWN);
chk_err(1'b0, bank, SELF_REF, PWR_DOWN);
if (|auto_precharge_bank) begin
$display ("%m: at time %t ERROR: Power Down Failure. Auto Precharge is scheduled.", $time);
if (STOP_ON_ERROR) $stop(0);
init_done = 0;
end else if (init_done) begin
if (DEBUG) begin
if (|active_bank) begin
$display ("%m: at time %t INFO: Active Power Down Enter", $time);
end else begin
$display ("%m: at time %t INFO: Precharge Power Down Enter", $time);
end
end
in_power_down = 1;
end
end
default : begin
$display ("%m: at time %t ERROR: NOP, Deselect, or Refresh is required when CKE goes inactive.", $time);
init_done = 0;
end
endcase
if (!init_done) begin
if (DEBUG) $display ("%m: at time %t INFO: Reset has occurred.", $time);
reset_task;
end
end
prev_cke = cke;
end
endtask
task data_task;
reg [BA_BITS-1:0] bank;
reg [ROW_BITS-1:0] row;
reg [COL_BITS-1:0] col;
integer i;
integer j;
begin
if (ck_in) begin
for (i=0; i<32; i=i+1) begin
if (data_in_valid && dll_locked && ($time - tm_dqs_neg[i] < $rtoi(TDSS*tck_avg)))
$display ("%m: at time %t ERROR: tDSS violation on %s bit %d", $time, dqs_string[i/16], i%16);
if (check_write_dqs_high[i])
$display ("%m: at time %t ERROR: %s bit %d latching edge required during the preceding clock period.", $time, dqs_string[i/16], i%16);
end
check_write_dqs_high <= 0;
end else if (!ck_in) begin
for (i=0; i<32; i=i+1) begin
if (dll_locked && data_in_valid) begin
tm_tdqss = abs_value(tm_ck_pos - tm_dqss_pos[i]);
if ((tm_tdqss < tck_avg/2.0) && (tm_tdqss > TDQSS*tck_avg))
$display ("%m: at time %t ERROR: tDQSS violation on %s bit %d", $time, dqs_string[i/16], i%16);
end
if (check_write_dqs_low[i])
$display ("%m: at time %t ERROR: %s bit %d latching edge required during the preceding clock period", $time, dqs_string[i/16], i%16);
end
check_write_preamble <= 0;
check_write_postamble <= 0;
check_write_dqs_low <= 0;
end
if (wr_pipeline[0] || rd_pipeline[0]) begin
bank = ba_pipeline[0];
row = row_pipeline[0];
col = col_pipeline[0];
burst_cntr = 0;
memory_read(bank, row, col, memory_data);
end
// burst counter
if (burst_cntr < burst_length) begin
burst_position = col ^ burst_cntr;
if (!burst_order) begin
burst_position[BO_BITS-1:0] = col + burst_cntr;
end
burst_cntr = burst_cntr + 1;
end
// write dqs counter
if (wr_pipeline[WDQS_PRE + 1]) begin
wdqs_cntr = WDQS_PRE + burst_length + WDQS_PST - 1;
end
// write dqs
if ((wdqs_cntr == burst_length + WDQS_PST) && (wdq_cntr == 0)) begin //write preamble
check_write_preamble <= ({DQS_BITS{dqs_n_en}}<<16) | {DQS_BITS{1'b1}};
end
if (wdqs_cntr > 1) begin // write data
if ((wdqs_cntr - WDQS_PST)%2) begin
check_write_dqs_high <= ({DQS_BITS{dqs_n_en}}<<16) | {DQS_BITS{1'b1}};
end else begin
check_write_dqs_low <= ({DQS_BITS{dqs_n_en}}<<16) | {DQS_BITS{1'b1}};
end
end
if (wdqs_cntr == WDQS_PST) begin // write postamble
check_write_postamble <= ({DQS_BITS{dqs_n_en}}<<16) | {DQS_BITS{1'b1}};
end
if (wdqs_cntr > 0) begin
wdqs_cntr = wdqs_cntr - 1;
end
// write dq
if (data_in_valid) begin // write data
bit_mask = 0;
if (ck_in) begin
for (i=0; i<DM_BITS; i=i+1) begin
bit_mask = bit_mask | ({`DQ_PER_DQS{~dm_in_neg[i]}}<<(burst_position*DQ_BITS + i*`DQ_PER_DQS))?? 快捷鍵說明
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