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68030tk/Logic/68030-68000-bus-kaputt2.vhd

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VHDL
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library ieee;
use ieee.std_logic_1164.all;
use ieee.std_logic_arith.all;
use ieee.std_logic_unsigned.all;
entity BUS68030 is
port(
AS_030: inout std_logic ;
AS_000: inout std_logic ;
-- DS_030: inout std_logic ;
UDS_000: inout std_logic;
LDS_000: inout std_logic;
SIZE: inout std_logic_vector ( 1 downto 0 );
A: inout std_logic_vector ( 31 downto 0 );
CPU_SPACE: in std_logic ;
-- BERR: inout std_logic ; --error: this is connected to a global input pin :(
BG_030: in std_logic ;
BG_000: out std_logic ;
BGACK_030: out std_logic ;
BGACK_000: in std_logic ;
CLK_030: in std_logic ;
CLK_000: in std_logic ;
CLK_OSZI: in std_logic ;
CLK_DIV_OUT: out std_logic ;
CLK_EXP: out std_logic ;
FPU_CS: out std_logic ;
IPL_030: out std_logic_vector ( 2 downto 0 );
IPL: in std_logic_vector ( 2 downto 0 );
DSACK: inout std_logic_vector ( 1 downto 0 );
DTACK: inout std_logic ;
AVEC: out std_logic ;
-- AVEC_EXP: inout std_logic ; --this is a "free pin"
E: out std_logic ;
VPA: in std_logic ;
VMA: out std_logic ;
RST: in std_logic ;
RESET: out std_logic ;
RW: in std_logic ;
-- D: inout std_logic_vector ( 31 downto 28 );
FC: in std_logic_vector ( 1 downto 0 );
AMIGA_BUS_ENABLE: out std_logic ;
AMIGA_BUS_DATA_DIR: out std_logic ;
AMIGA_BUS_ENABLE_LOW: out std_logic;
CIIN: out std_logic
);
end BUS68030;
architecture Behavioral of BUS68030 is
subtype ESTATE is std_logic_vector(3 downto 0);
constant E1 : ESTATE := "0110";
constant E2 : ESTATE := "0111";
constant E3 : ESTATE := "0100";
constant E4 : ESTATE := "0101";
constant E5 : ESTATE := "0010";
constant E6 : ESTATE := "0011";
constant E7 : ESTATE := "1010";
constant E8 : ESTATE := "1011";
constant E9 : ESTATE := "1100";
constant E10 : ESTATE := "1111";
-- Illegal states
constant E20 : ESTATE := "0000";
constant E4a : ESTATE := "0001";
constant E21 : ESTATE := "1000";
constant E22 : ESTATE := "1001";
constant E23 : ESTATE := "1101";
constant E24 : ESTATE := "1110";
signal cpu_est : ESTATE := E20;
subtype AMIGA_STATE is std_logic_vector(1 downto 0);
constant IDLE : AMIGA_STATE := "00";
constant AS_SET : AMIGA_STATE := "01";
constant DATA_FETCH : AMIGA_STATE := "10";
constant END_CYCLE : AMIGA_STATE := "11";
signal SM_AMIGA : AMIGA_STATE;
signal SM_AMIGA_LAST : AMIGA_STATE;
--signal Dout:STD_LOGIC_VECTOR(3 downto 0) := "0000";
signal ZorroII:STD_LOGIC:= '0';
signal AS_000_INT:STD_LOGIC:= '1';
signal AS_000_INT_D:STD_LOGIC:= '1';
signal BGACK_030_INT:STD_LOGIC:= '1';
signal DTACK_DMA:STD_LOGIC:= '1';
signal DTACK_INT:STD_LOGIC:= '1';
signal DTACK_SYNC:STD_LOGIC:= '1';
signal DTACK_SYNC_D:STD_LOGIC:= '1';
signal DTACK_SYNC_DD:STD_LOGIC:= '1';
signal FPU_CS_INT:STD_LOGIC:= '1';
signal E_INT: STD_LOGIC:='1';
signal VPA_SYNC: STD_LOGIC:='1';
signal VMA_INT: STD_LOGIC:='1';
signal VMA_INT_D: STD_LOGIC:='1';
signal UDS_000_INT: STD_LOGIC:='1';
signal LDS_000_INT: STD_LOGIC:='1';
signal UDS_LOGIC: STD_LOGIC:='1';
signal LDS_LOGIC: STD_LOGIC:='1';
--signal AS_030_delay: STD_LOGIC:='1';
signal SM_AMIGA_ENABLE: STD_LOGIC:='1';
--signal DS_030_INT: STD_LOGIC:='Z';
--signal A_INT: STD_LOGIC_VECTOR ( 1 downto 0 ) := "00";
--signal SIZE_INT: STD_LOGIC_VECTOR ( 1 downto 0 ) := "00";
signal DSACK_INT: STD_LOGIC_VECTOR ( 1 downto 0 ) := "11";
signal CLK_CNT: STD_LOGIC_VECTOR ( 1 downto 0 ) := "00";
signal CLK_OUT_INT: STD_LOGIC:='1';
signal CLK_000_D: STD_LOGIC := '1';
begin
--clk generation : up to now just half the clock
cpu_clk: process(CLK_OSZI)
begin
if(rising_edge(CLK_OSZI)) then
if(CLK_CNT="01") then
CLK_OUT_INT <= not CLK_OUT_INT;
CLK_CNT <= "00";
else
CLK_CNT <= CLK_CNT+1;
end if;
end if;
end process cpu_clk;
CLK_DIV_OUT <= CLK_OUT_INT;
CLK_EXP <= CLK_OUT_INT;
clk_delay: process(CLK_030)
begin
if(rising_edge(CLK_030)) then
CLK_000_D <= CLK_000;
end if;
end process clk_delay;
--ZORROII (Amiga) space?
ZorroII <= '1' when (A(31 downto 24)= x"00") else '0'; -- 24-bit addres space.
--BG_ACK is simple:
BGACK_030_gen: process (CLK_000,BGACK_000) begin
if(BGACK_000='0') then
BGACK_030_INT <= '0';
elsif rising_edge(CLK_000) then
BGACK_030_INT <= '1'; --hold this signal high until 7m clock goes high
end if;
end process BGACK_030_gen;
BGACK_030 <= BGACK_030_INT;
--DTACK
DTACK <= 'Z' when BGACK_030_INT ='1' else
DTACK_DMA;
DTACK_DMA <= '0' when AS_000_INT ='0' AND DSACK(1) ='0' else
'1';
--CO-Processor Chip select
FPU_CS_INT <= '0' when FC(1)='1' and FC(0)='1' and A(19)='0' and A(18)='0' and A(17)='1' and A(16)='0' AND BGACK_000='0'
else '1';
FPU_CS <= FPU_CS_INT;
--if no copro is installed:
-- BERR <= 'Z' when FPU_CS_INT ='1' else '0';
--reset buffer
RESET <= RST;
--cache inhibit: For now: disable
CIIN <= '1' WHEN A(31 downto 20) = x"00F" ELSE
'1' WHEN A(31 downto 16) = x"00E0" ELSE
'0';
--bus buffers
AMIGA_BUS_ENABLE <= '0'; --for now: allways on
AMIGA_BUS_DATA_DIR <='1' WHEN RW='0' ELSE '0';
AMIGA_BUS_ENABLE_LOW <= '1'; --for now: allways off
-- vma and e clock
e_clk: process (CLK_000)
begin
if rising_edge(CLK_000) then
-- next state.
case (cpu_est) is
when E1 => cpu_est <= E2 ;
when E2 => cpu_est <= E3 ;
when E3 => cpu_est <= E4;
when E4 => cpu_est <= E5 ;
when E5 => cpu_est <= E6 ;
when E6 => cpu_est <= E7 ;
when E7 => cpu_est <= E8 ;
when E8 => cpu_est <= E9 ;
when E9 => cpu_est <= E10;
when E10 => cpu_est <= E1 ;
-- Illegal states
when E4a => cpu_est <= E5 ;
when E20 => cpu_est <= E10;
when E21 => cpu_est <= E10;
when E22 => cpu_est <= E9 ;
when E23 => cpu_est <= E9 ;
when E24 => cpu_est <= E10;
when others =>
null;
end case;
end if;
end process e_clk;
vma_gen: process (CLK_000,AS_030) begin
if(AS_030='1') then
VMA_INT <= '1';
VPA_SYNC <= '1';
elsif falling_edge(CLK_000) then
VPA_SYNC <= VPA;
if(cpu_est = E3 AND VPA_SYNC = '0' AND AS_000_INT = '0') then
VMA_INT <= '0'; -- low active !
end if;
if(cpu_est = E10) then
VMA_INT <= '1';
end if;
end if;
end process vma_gen;
vma_delay: process(CLK_030)
begin
if(rising_edge(CLK_030)) then
VMA_INT_D<=VMA_INT;
end if;
end process vma_delay;
E_INT <= cpu_est(3);
E <= E_INT;
VMA <= VMA_INT AND VMA_INT_D;
--AVEC
--AVEC <= '0' WHEN VMA='1' AND cpu_est = E10 --
-- ELSE '1';
AVEC <= '1';
--IPL: Buffer interrupts for a CPU-Cycle to avoid fake interupts
ipl_amiga: process(CLK_000)
begin
if(rising_edge(CLK_000)) then
IPL_030<=IPL;
end if;
end process ipl_amiga;
--BG
bg_amiga: process(CLK_030,BG_030)
begin
if(BG_030= '1')then
BG_000 <= '1';
elsif(falling_edge(CLK_030)) then
if(SM_AMIGA = IDLE and CPU_SPACE = '0' and AS_030='1') then --bus granted no local access and no AS_030 running!
BG_000 <= '0';
else
BG_000 <='1';
end if;
end if;
end process bg_amiga;
--as uds/lds generation
UDS_LOGIC <= '0' WHEN AS_030 = '0' AND A(0)='0' ELSE '1';
LDS_LOGIC <= '0' WHEN AS_030 = '0' AND (A(0)='1' OR SIZE(0)='0' OR SIZE(1)='1') ELSE '1';
--state machine for amiga-cycle
sm_amiga: process(RST, CLK_030)
begin
if(RST='0') then
SM_AMIGA <= IDLE;
DTACK_INT <= '1';
DSACK_INT <="11";
UDS_000_INT <='1';
LDS_000_INT <='1';
AS_000_INT <='1';
SM_AMIGA_ENABLE <='0';
elsif(rising_edge(CLK_030)) then
case (SM_AMIGA) is
when IDLE =>
if(CLK_000 ='0') then
SM_AMIGA_ENABLE<='1';
end if;
if ( AS_030 = '0' -- obviously as must be low
AND CPU_SPACE = '0' -- expansion board not in action
AND CLK_000 = '1' --AND CLK_000_D = '1' -- as is sampled at falling edge on a 68000/010 thus it is set during high CLK_000
AND SM_AMIGA_ENABLE = '1'
) then
AS_000_INT <= '0';
if (RW='1') then --read: set udl/lds
UDS_000_INT <= UDS_LOGIC;
LDS_000_INT <= LDS_LOGIC;
end if;
SM_AMIGA_ENABLE <='0';
SM_AMIGA <= AS_SET;
else
DSACK_INT<="11";
UDS_000_INT <='1';
LDS_000_INT <='1';
AS_000_INT <='1';
end if;
when AS_SET =>
if(CLK_000 ='0') then
SM_AMIGA_ENABLE<='1';
end if;
if ( CLK_000 = '1' and SM_AMIGA_ENABLE='1' ) then
UDS_000_INT <= UDS_LOGIC;
LDS_000_INT <= LDS_LOGIC;
if(VPA_SYNC = '1' AND DTACK='0') then
DTACK_INT<= '0';
SM_AMIGA_ENABLE <='0';
SM_AMIGA <= DATA_FETCH ;
elsif(E10=cpu_est AND VPA_SYNC='0' AND VMA_INT='0') then --vpa/vma cycle
DTACK_INT<= '0';
SM_AMIGA_ENABLE <='0';
SM_AMIGA <= DATA_FETCH ;
end if;
end if;
when DATA_FETCH => --here the data is written/read
DSACK_INT<="01";
if(CLK_000_D ='0') then
SM_AMIGA_ENABLE<='1';
end if;
if(AS_030 ='1') then
DSACK_INT<="11";
UDS_000_INT <='1';
LDS_000_INT <='1';
AS_000_INT <='1';
end if;
if( CLK_000 = '1' AND SM_AMIGA_ENABLE = '1')then
SM_AMIGA_ENABLE <='0';
SM_AMIGA <= END_CYCLE;
end if;
when END_CYCLE => -- internal DTACK is high here. end cycle!
if(CLK_000 ='0') then
SM_AMIGA_ENABLE<='1';
end if;
if(AS_030 ='1') then
DSACK_INT<="11";
UDS_000_INT <='1';
LDS_000_INT <='1';
AS_000_INT <='1';
end if;
if ( CLK_000 = '1' and SM_AMIGA_ENABLE <='1' ) then
SM_AMIGA_ENABLE <='0';
SM_AMIGA <= IDLE ;
end if;
end case;
end if;
end process sm_amiga;
AS_000 <= 'Z' when BGACK_030_INT ='0' else
AS_000_INT;
UDS_000 <= 'Z' when BGACK_030_INT ='0' else -- output on cpu cycle
UDS_000_INT;
LDS_000 <= 'Z' when BGACK_030_INT ='0' else -- output on cpu cycle
LDS_000_INT;
DSACK <= "ZZ" when CPU_SPACE = '1' else -- output on amiga cycle
DSACK_INT;
-- signal assignment
--DS_030 <= "ZZ";
--DS_030 <= "ZZ" when BGACK_030_INT ='1' else -- output on dma cycle
-- DS_030_INT;
--A(1) <= 'Z';
--A(0) <= 'Z';
--A[1 downto 0] <= "ZZ" when BGACK_030_INT ='1' else -- output on dma cycle
-- A_INT;
--SIZE <= "ZZ";
--SIZE <= "ZZ" when BGACK_030_INT ='1' else -- output on dma cycle
-- SIZE_INT;
end Behavioral;
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