?? mt48lc8m16a2.vhd
字號:
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) := TO_BITVECTOR (Addr(col_bits - 1 DOWNTO 0));
Bank_addr (0) := TO_BITVECTOR (Ba);
-- Write intterupt a Write (terminate Write immediately)
IF Data_in_enable = '1' THEN
Data_in_enable := '0';
IF Auto_precharge(TO_INTEGER(Bank)) = '1' AND Write_precharge(TO_INTEGER(Bank)) = '1' THEN
RW_interrupt_write(TO_INTEGER(Bank)) := '1';
END IF;
END IF;
-- Write interrupt a Read (terminate Read immediately)
IF Data_out_enable = '1' THEN
Data_out_enable := '0';
IF Auto_precharge(TO_INTEGER(Bank)) = '1' AND Read_precharge(TO_INTEGER(Bank)) = '1' THEN
RW_interrupt_read(TO_INTEGER(Bank)) := '1';
END IF;
END IF;
END IF;
-- Read or Write with Auto Precharge
IF Addr(10) = '1' THEN
Auto_precharge (TO_INTEGER(Ba)) := '1';
Count_precharge (TO_INTEGER(Ba)) := 0;
IF Read_enable = '1' THEN
Read_precharge (TO_INTEGER(Ba)) := '1';
ELSIF Write_enable = '1' THEN
Write_precharge (TO_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;
-- Write with AutoPrecharge Calculation
-- The device start internal precharge when:
-- 1. tWR 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 (Write_precharge(0) = '1')) THEN
IF (((NOW - RAS_chk0 >= tRAS) AND
(((Burst_length_1 = '1' OR Write_burst_mode = '1' ) AND Count_precharge(0) >= 2) OR
(Burst_length_2 = '1' AND Count_precharge(0) >= 3) OR
(Burst_length_4 = '1' AND Count_precharge(0) >= 5) OR
(Burst_length_8 = '1' AND Count_precharge(0) >= 9))) OR
(RW_interrupt_write(0) = '1' AND WR_chk(0) >= 3)) THEN
Pc_b0 := '1';
Act_b0 := '0';
RP_chk0 := NOW;
Auto_precharge(0) := '0';
Write_precharge(0) := '0';
RW_interrupt_write(0) := '0';
END IF;
END IF;
IF ((Auto_precharge(1) = '1') AND (Write_precharge(1) = '1')) THEN
IF (((NOW - RAS_chk1 >= tRAS) AND
(((Burst_length_1 = '1' OR Write_burst_mode = '1' ) AND Count_precharge(1) >= 2) OR
(Burst_length_2 = '1' AND Count_precharge(1) >= 3) OR
(Burst_length_4 = '1' AND Count_precharge(1) >= 5) OR
(Burst_length_8 = '1' AND Count_precharge(1) >= 9))) OR
(RW_interrupt_write(1) = '1' AND WR_chk(1) >= 3)) THEN
Pc_b1 := '1';
Act_b1 := '0';
RP_chk1 := NOW;
Auto_precharge(1) := '0';
Write_precharge(1) := '0';
RW_interrupt_write(1) := '0';
END IF;
END IF;
IF ((Auto_precharge(2) = '1') AND (Write_precharge(2) = '1')) THEN
IF (((NOW - RAS_chk2 >= tRAS) AND
(((Burst_length_1 = '1' OR Write_burst_mode = '1' ) AND Count_precharge(2) >= 2) OR
(Burst_length_2 = '1' AND Count_precharge(2) >= 3) OR
(Burst_length_4 = '1' AND Count_precharge(2) >= 5) OR
(Burst_length_8 = '1' AND Count_precharge(2) >= 9))) OR
(RW_interrupt_write(2) = '1' AND WR_chk(2) >= 3)) THEN
Pc_b2 := '1';
Act_b2 := '0';
RP_chk2 := NOW;
Auto_precharge(2) := '0';
Write_precharge(2) := '0';
RW_interrupt_write(2) := '0';
END IF;
END IF;
IF ((Auto_precharge(3) = '1') AND (Write_precharge(3) = '1')) THEN
IF (((NOW - RAS_chk3 >= tRAS) AND
(((Burst_length_1 = '1' OR Write_burst_mode = '1' ) AND Count_precharge(3) >= 2) OR
(Burst_length_2 = '1' AND Count_precharge(3) >= 3) OR
(Burst_length_4 = '1' AND Count_precharge(3) >= 5) OR
(Burst_length_8 = '1' AND Count_precharge(3) >= 9))) OR
(RW_interrupt_write(3) = '1' AND WR_chk(3) >= 3)) THEN
Pc_b3 := '1';
Act_b3 := '0';
RP_chk3 := NOW;
Auto_precharge(3) := '0';
Write_precharge(3) := '0';
RW_interrupt_write(3) := '0';
END IF;
END IF;
-- Internal Precharge or Bst
IF Command(0) = PRECH THEN -- 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 -- Terminate a read immediately
IF Data_out_enable = '1' THEN
Data_out_enable := '0';
END IF;
END IF;
IF Data_out_enable = '0' THEN
Dq <= TRANSPORT (OTHERS => 'Z') AFTER tOH;
END IF;
-- Detect Read or Write Command
IF Command(0) = READ OR Command(0) = READ_A THEN
Bank := Bank_addr (0);
Col := Col_addr (0);
Col_brst := Col_addr (0);
IF Bank_addr (0) = "00" THEN
Row := B0_row_addr;
ELSIF Bank_addr (0) = "01" THEN
Row := B1_row_addr;
ELSIF Bank_addr (0) = "10" THEN
Row := B2_row_addr;
ELSE
Row := B3_row_addr;
END IF;
Burst_counter := 0;
Data_in_enable := '0';
Data_out_enable := '1';
ELSIF Command(0) = WRITE OR Command(0) = WRITE_A THEN
Bank := Bank_addr(0);
Col := Col_addr(0);
Col_brst := Col_addr(0);
IF Bank_addr (0) = "00" THEN
Row := B0_row_addr;
ELSIF Bank_addr (0) = "01" THEN
Row := B1_row_addr;
ELSIF Bank_addr (0) = "10" THEN
Row := B2_row_addr;
ELSE
Row := B3_row_addr;
END IF;
Burst_counter := 0;
Data_in_enable := '1';
Data_out_enable := '0';
END IF;
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