?? mt48lc2m32b2_2.vhd
字號:
Previous_bank := Ba;
END IF;
-- Precharge Block
IF Prech_enable = '1' THEN
IF Addr(10) = '1' THEN
Pc_b0 := '1';
Pc_b1 := '1';
Pc_b2 := '1';
Pc_b3 := '1';
Act_b0 := '0';
Act_b1 := '0';
Act_b2 := '0';
Act_b3 := '0';
RP_chk0 := NOW;
RP_chk1 := NOW;
RP_chk2 := NOW;
RP_chk3 := NOW;
-- Activate to Precharge all banks
ASSERT ((NOW - RAS_chk0 >= tRAS) OR (NOW - RAS_chk1 >= tRAS))
REPORT "tRAS violation during Precharge all banks"
SEVERITY WARNING;
-- tWR violation check for Write
IF ((NOW - WR_chkp(0) < tWRp) OR (NOW - WR_chkp(1) < tWRp) OR
(NOW - WR_chkp(2) < tWRp) OR (NOW - WR_chkp(3) < tWRp)) THEN
ASSERT (FALSE)
REPORT "tWR violation during Precharge ALL banks"
SEVERITY WARNING;
END IF;
ELSIF Addr(10) = '0' THEN
IF Ba = "00" THEN
Pc_b0 := '1';
Act_b0 := '0';
RP_chk0 := NOW;
-- Activate to Precharge bank 0
ASSERT (NOW - RAS_chk0 >= tRAS)
REPORT "tRAS violation during Precharge bank 0"
SEVERITY WARNING;
ELSIF Ba = "01" THEN
Pc_b1 := '1';
Act_b1 := '0';
RP_chk1 := NOW;
-- Activate to Precharge bank 1
ASSERT (NOW - RAS_chk1 >= tRAS)
REPORT "tRAS violation during Precharge bank 1"
SEVERITY WARNING;
ELSIF Ba = "10" THEN
Pc_b2 := '1';
Act_b2 := '0';
RP_chk2 := NOW;
-- Activate to Precharge bank 2
ASSERT (NOW - RAS_chk2 >= tRAS)
REPORT "tRAS violation during Precharge bank 2"
SEVERITY WARNING;
ELSIF Ba = "11" THEN
Pc_b3 := '1';
Act_b3 := '0';
RP_chk3 := NOW;
-- Activate to Precharge bank 3
ASSERT (NOW - RAS_chk3 >= tRAS)
REPORT "tRAS violation during Precharge bank 3"
SEVERITY WARNING;
END IF;
-- tWR violation check for Write
ASSERT (NOW - WR_chkp(CONV_INTEGER(Ba)) >= tWRp)
REPORT "tWR violation during Precharge"
SEVERITY WARNING;
END IF;
-- Terminate a Write Immediately (if same bank or all banks)
IF (Data_in_enable = '1' AND (Bank = Ba OR Addr(10) = '1')) THEN
Data_in_enable := '0';
END IF;
-- Precharge Command Pipeline for READ
IF CAS_latency_3 = '1' THEN
Command(2) := PRECH;
Bank_precharge(2) := Ba;
A10_precharge(2) := Addr(10);
ELSIF CAS_latency_2 = '1' THEN
Command(1) := PRECH;
Bank_precharge(1) := Ba;
A10_precharge(1) := Addr(10);
END IF;
END IF;
-- Burst Terminate
IF Burst_term = '1' THEN
-- Terminate a Write immediately
IF Data_in_enable = '1' THEN
Data_in_enable := '0';
END IF;
-- Terminate a Read depend on CAS Latency
IF CAS_latency_3 = '1' THEN
Command(2) := BST;
ELSIF CAS_latency_2 = '1' THEN
Command(1) := BST;
END IF;
END IF;
-- Read, Write, Column Latch
IF Read_enable = '1' OR Write_enable = '1' THEN
-- Check to see if bank is open (ACT) for Read or Write
IF ((Ba = "00" AND Pc_b0 = '1') OR (Ba = "01" AND Pc_b1 = '1') OR
(Ba = "10" AND Pc_b2 = '1') OR (Ba = "11" AND Pc_b3 = '1')) THEN
ASSERT (FALSE)
REPORT "Cannot Read or Write - Bank is not Activated"
SEVERITY WARNING;
END IF;
-- Activate to Read or Write
IF Ba = "00" THEN
ASSERT (NOW - RCD_chk0 >= tRCD)
REPORT "tRCD violation during Read or Write to Bank 0"
SEVERITY WARNING;
ELSIF Ba = "01" THEN
ASSERT (NOW - RCD_chk1 >= tRCD)
REPORT "tRCD violation during Read or Write to Bank 1"
SEVERITY WARNING;
ELSIF Ba = "10" THEN
ASSERT (NOW - RCD_chk2 >= tRCD)
REPORT "tRCD violation during Read or Write to Bank 2"
SEVERITY WARNING;
ELSIF Ba = "11" THEN
ASSERT (NOW - RCD_chk3 >= tRCD)
REPORT "tRCD violation during Read or Write to Bank 3"
SEVERITY WARNING;
END IF;
-- Read Command
IF Read_enable = '1' THEN
-- CAS Latency Pipeline
IF Cas_latency_1 = '1' THEN
IF Addr(10) = '1' THEN
Command(0) := READ_A;
ELSE
Command(0) := READ;
END IF;
Col_addr (0) := Addr(col_bits - 1 DOWNTO 0);
Bank_addr (0) := Ba;
ELSIF Cas_latency_2 = '1' THEN
IF Addr(10) = '1' THEN
Command(1) := READ_A;
ELSE
Command(1) := READ;
END IF;
Col_addr (1) := Addr(col_bits - 1 DOWNTO 0);
Bank_addr (1) := Ba;
ELSIF Cas_latency_3 = '1' THEN
IF Addr(10) = '1' THEN
Command(2) := READ_A;
ELSE
Command(2) := READ;
END IF;
Col_addr (2) := Addr(col_bits - 1 DOWNTO 0);
Bank_addr (2) := Ba;
END IF;
-- Read intterupt a Write (terminate Write immediately)
IF Data_in_enable = '1' THEN
Data_in_enable := '0';
-- Interrupt a write with autoprecharge
IF (Auto_precharge (CONV_INTEGER(RW_interrupt_bank)) = '1' AND
Write_precharge (CONV_INTEGER(RW_interrupt_bank)) = '1') THEN
RW_interrupt_write (CONV_INTEGER(RW_interrupt_bank)) := '1';
WR_time (CONV_INTEGER(RW_interrupt_bank)) := NOW;
END IF;
END IF;
-- Write Command
ELSIF Write_enable = '1' THEN
IF Addr(10) = '1' THEN
Command(0) := WRITE_A;
ELSE
Command(0) := WRITE;
END IF;
Col_addr (0) := Addr(col_bits - 1 DOWNTO 0);
Bank_addr (0) := Ba;
-- Write intterupt a Write (terminate Write immediately)
IF Data_in_enable = '1' THEN
Data_in_enable := '0';
-- Interrupt a Write with Auto Precharge
IF (Auto_precharge(CONV_INTEGER(RW_interrupt_bank)) = '1' AND
Write_precharge(CONV_INTEGER(RW_interrupt_bank)) = '1') THEN
RW_interrupt_write(CONV_INTEGER(RW_interrupt_bank)) := '1';
WR_time (CONV_INTEGER(RW_interrupt_bank)) := NOW;
END IF;
END IF;
-- Write interrupt a Read (terminate Read immediately)
IF Data_out_enable = '1' THEN
Data_out_enable := '0';
-- Interrupt a Read with Auto Precharge
IF Auto_precharge(CONV_INTEGER(RW_interrupt_bank)) = '1' AND Read_precharge(CONV_INTEGER(RW_interrupt_bank)) = '1' THEN
RW_interrupt_read(CONV_INTEGER(RW_interrupt_bank)) := '1';
END IF;
END IF;
END IF;
-- Read or Write with Auto Precharge
IF Addr(10) = '1' THEN
Auto_precharge (CONV_INTEGER(Ba)) := '1';
Count_precharge (CONV_INTEGER(Ba)) := 0;
RW_interrupt_bank := Ba;
IF Read_enable = '1' THEN
Read_precharge (CONV_INTEGER(Ba)) := '1';
ELSIF Write_enable = '1' THEN
Write_precharge (CONV_INTEGER(Ba)) := '1';
END IF;
END IF;
END IF;
-- Read with AutoPrecharge Calculation
-- The device start internal precharge when:
-- 1. BL/2 cycles after command
-- and 2. Meet tRAS requirement
-- or 3. Interrupt by a Read or Write (with or without Auto Precharge)
IF ((Auto_precharge(0) = '1') AND (Read_precharge(0) = '1')) THEN
IF (((NOW - RAS_chk0 >= tRAS) AND
((Burst_length_1 = '1' AND Count_precharge(0) >= 1) OR
(Burst_length_2 = '1' AND Count_precharge(0) >= 2) OR
(Burst_length_4 = '1' AND Count_precharge(0) >= 4) OR
(Burst_length_8 = '1' AND Count_precharge(0) >= 8))) OR
(RW_interrupt_read(0) = '1')) THEN
Pc_b0 := '1';
Act_b0 := '0';
RP_chk0 := NOW;
Auto_precharge(0) := '0';
Read_precharge(0) := '0';
RW_interrupt_read(0) := '0';
END IF;
END IF;
IF ((Auto_precharge(1) = '1') AND (Read_precharge(1) = '1')) THEN
IF (((NOW - RAS_chk1 >= tRAS) AND
((Burst_length_1 = '1' AND Count_precharge(1) >= 1) OR
(Burst_length_2 = '1' AND Count_precharge(1) >= 2) OR
(Burst_length_4 = '1' AND Count_precharge(1) >= 4) OR
(Burst_length_8 = '1' AND Count_precharge(1) >= 8))) OR
(RW_interrupt_read(1) = '1')) THEN
Pc_b1 := '1';
Act_b1 := '0';
RP_chk1 := NOW;
Auto_precharge(1) := '0';
Read_precharge(1) := '0';
RW_interrupt_read(1) := '0';
END IF;
END IF;
IF ((Auto_precharge(2) = '1') AND (Read_precharge(2) = '1')) THEN
IF (((NOW - RAS_chk2 >= tRAS) AND
((Burst_length_1 = '1' AND Count_precharge(2) >= 1) OR
(Burst_length_2 = '1' AND Count_precharge(2) >= 2) OR
(Burst_length_4 = '1' AND Count_precharge(2) >= 4) OR
(Burst_length_8 = '1' AND Count_precharge(2) >= 8))) OR
(RW_interrupt_read(2) = '1')) THEN
Pc_b2 := '1';
Act_b2 := '0';
RP_chk2 := NOW;
Auto_precharge(2) := '0';
Read_precharge(2) := '0';
RW_interrupt_read(2) := '0';
END IF;
END IF;
IF ((Auto_precharge(3) = '1') AND (Read_precharge(3) = '1')) THEN
IF (((NOW - RAS_chk3 >= tRAS) AND
((Burst_length_1 = '1' AND Count_precharge(3) >= 1) OR
(Burst_length_2 = '1' AND Count_precharge(3) >= 2) OR
(Burst_length_4 = '1' AND Count_precharge(3) >= 4) OR
(Burst_length_8 = '1' AND Count_precharge(3) >= 8))) OR
(RW_interrupt_read(3) = '1')) THEN
Pc_b3 := '1';
Act_b3 := '0';
RP_chk3 := NOW;
Auto_precharge(3) := '0';
Read_precharge(3) := '0';
RW_interrupt_read(3) := '0';
END IF;
END IF;
-- Internal Precharge or Bst
IF Command(0) = PRECH THEN -- PRECH terminate a read if same bank or all banks
IF Bank_precharge(0) = Bank OR A10_precharge(0) = '1' THEN
IF Data_out_enable = '1' THEN
Data_out_enable := '0';
END IF;
END IF;
ELSIF Command(0) = BST THEN -- BST terminate a read regardless of bank
IF Data_out_enable = '1' THEN
Data_out_enable := '0';
END IF;
END IF;
-- Turn off databus
IF (Data_out_enable = '0') THEN
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