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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 i43cpld is
generic(
FPGASize : std_logic := '0' -- FPGA size 0 = 200K, 1 = 400K
);
Port (
clk : in std_logic;
opt : in std_logic_vector(1 downto 0);
nreset : in std_logic;
usbnrd : out std_logic;
usbwr : out std_logic;
-- usbntxe : in std_logic;
usbnrxf : in std_logic;
fpganrdwr : out std_logic;
fpgancs_paramode : inout std_logic;
fpganreconfig : in std_logic;
fpganprogram : out std_logic;
fpgadone : in std_logic;
fpgacclk : inout std_logic;
fpgaserial : out std_logic;
fpgaconfigd0 : out std_logic;
fpganinit: in std_logic;
fpga_epp_astrobe: out std_logic;
fpga_epp_dstrobe: out std_logic;
fpga_epp_read: out std_logic;
fpga_epp_wait: in std_logic;
cmdo : in std_logic;
cmdi : out std_logic;
cmcs : out std_logic;
nstrobe_nwrite : in std_logic;
ninit : in std_logic;
autofd_dstrobe : in std_logic;
selectin_astrobe : in std_logic;
busy_wait : out std_logic;
fault : out std_logic;
perror : out std_logic;
busd0 : inout std_logic);
end i43cpld;
architecture Behavioral of i43cpld is
type configtype is (para,usb,spi,done);
signal configmode : configtype;
signal fcnt : std_logic_vector(1 downto 0);
signal filter : std_logic_vector(1 downto 0);
signal waitpipe : std_logic_vector(4 downto 0);
signal para_cclk : std_logic;
signal para_program : std_logic;
signal para_wait: std_logic;
signal dautofd_dstrobe: std_logic;
signal dselectin_astrobe: std_logic;
signal alatch : std_logic;
signal dwrite : std_logic;
signal awrite : std_logic;
signal usb_cclk : std_logic;
signal dusb_cclk : std_logic;
signal usb_echo : std_logic := '1';
signal rdtimer: std_logic_vector(3 downto 0);
signal usbtxoffsr: std_logic_vector(3 downto 0) := x"F";
alias usblastd0 : std_logic is usbtxoffsr(0);
signal dusbnrxf : std_logic;
signal usbconfigread : std_logic;
signal usbconfigwrite : std_logic;
signal usbwritetsen : std_logic;
signal spi_program : std_logic;
signal spi_cmcs : std_logic;
signal spi_cmdi : std_logic;
signal spi_cclk : std_logic;
signal pdelcounter : std_logic_vector(11 downto 0);
signal lastcounts : std_logic_vector(3 downto 0);
signal spiprescale : std_logic_vector(3 downto 0);
signal eestate : std_logic_vector(3 downto 0);
signal senddata : std_logic;
signal dospiconfig : std_logic;
begin
paraconfig: process(clk,waitpipe, alatch, filter, nstrobe_nwrite,
autofd_dstrobe, selectin_astrobe)
begin
if rising_edge(clk) then
dautofd_dstrobe <= autofd_dstrobe; -- 1st stage sync FF
dselectin_astrobe <= selectin_astrobe; -- 1st stage sync FF
filter(1) <= filter(0);
if dautofd_dstrobe = '0' or dselectin_astrobe = '0' then
waitpipe <= waitpipe(3 downto 0) & '1';
if fcnt /= "11" then
fcnt <= fcnt +1;
end if;
else
waitpipe <= "00000";
if fcnt /= "00" then
fcnt <= fcnt -1;
end if;
end if;
if fcnt = "11" then
filter(0) <= '1';
end if;
if fcnt = "00" then
filter(0) <= '0';
end if;
if awrite = '1' then
alatch <= busd0;
end if;
if dwrite = '1' and alatch = '1' then
para_program <= busd0;
end if;
end if; -- clk
para_wait <= waitpipe(4);
if filter = "01" and nstrobe_nwrite = '0' and dautofd_dstrobe = '0' then
dwrite <= '1';
else
dwrite <= '0';
end if;
if filter = "01" and nstrobe_nwrite = '0' and dselectin_astrobe = '0' then
awrite <= '1';
else
awrite <= '0';
end if;
if dwrite = '1' and alatch = '0' then
para_cclk <= '1';
else
para_cclk <= '0';
end if;
end process paraconfig;
usbconfig: process(clk, rdtimer)
begin
if rising_edge(clk) then
dusbnrxf <= usbnrxf; -- async so need 1 FF sync
dusb_cclk <= usb_cclk;
usbwritetsen <= usbconfigwrite; -- delayed one clock for data hold time
if rdtimer /= "0000" then
rdtimer <= rdtimer -1;
end if;
if rdtimer = "0000" and dusbnrxf = '0' then
rdtimer <= "1111";
end if;
if usb_cclk= '1' and dusb_cclk = '0' then
usbtxoffsr <= usbtxoffsr(2 downto 0)& busd0; -- left shift 20 ns after rising edge of cclk
end if;
if usbtxoffsr = x"0" then -- if host has sent 4 characters in a row with '1' lsb, turn off echo
usb_echo <= '0';
end if;
if (nreset = '0') or (fpganreconfig = '0') then -- enable usbecho at startup or reconfig
usb_echo <= '1';
usbtxoffsr <= x"F";
end if;
dusb_cclk <= usb_cclk;
end if; -- clk
usbconfigwrite <= not rdtimer(3) and (rdtimer(2) xor rdtimer(1)) and usb_echo;
usbconfigread <= not rdtimer(3);
usb_cclk <= rdtimer(3) and not rdtimer(2);
end process usbconfig;
spiconfig : process (clk)
begin
if rising_edge(clk) then
if (nreset = '0') or (fpganreconfig = '0') then
spi_program <= '0';
spi_cmcs <= '1';
spi_cmdi <= '0';
spi_cclk <= '0';
senddata <= '0';
eestate <= x"0";
pdelcounter <= x"000";
spiprescale <= x"0";
lastcounts <= x"0";
dospiconfig <= '1';
else
if dospiconfig = '1' then
spi_program <= '1';
spiprescale <= spiprescale +1;
spi_cclk <= spiprescale(3);
if spiprescale = x"0" then
pdelcounter <= pdelcounter + 1;
if pdelcounter(11) = '1' then
senddata <= '1';
end if;
if senddata = '1' then
if eestate /= 15 then
eestate <= eestate +1;
end if;
if eestate = 1 then
spi_cmcs <= '0';
end if;
if eestate = 7 then -- serial EEPROM read command needs ones from now on
spi_cmdi <= '1';
end if;
if fpgadone = '1' then
lastcounts <= lastcounts +1;
end if;
if lastcounts(3) = '1' then
dospiconfig <= '0';
spi_cmcs <= '1';
end if;
end if;
end if;
end if;
end if;
end if;
end process spiconfig;
doconfig : process (configmode,opt, spi_cclk, para_cclk, usb_cclk,
fpgadone, busd0, autofd_dstrobe, nstrobe_nwrite,
alatch, nreset, ninit, para_program, fpganinit,
para_wait, usbconfigread, cmdo, spi_program,
spi_cmcs, spi_cmdi, fpganreconfig, selectin_astrobe,
fpga_epp_wait)
begin
if opt(1) = '1' then
fpgaserial <= 'Z';
configmode <= spi;
fpgacclk <= spi_cclk;
else
fpgaserial <= '0';
if opt(0) = '0' then
configmode <= para;
fpgacclk <= para_cclk;
else
configmode <= usb;
fpgacclk <= usb_cclk;
end if;
end if;
if fpgadone = '1' then
configmode <= done;
end if;
case configmode is
when para =>
fpgaconfigd0 <= busd0;
if autofd_dstrobe = '0' and nstrobe_nwrite = '1' then
if alatch = '1' then
busd0 <= fpgadone;
else
busd0 <= FPGASize;
end if;
else
busd0 <= 'Z';
end if;
fpgancs_paramode <= '0';
fpganrdwr <= '0';
fpganprogram <= nreset and ninit and para_program;
cmcs <= 'Z';
cmdi <= 'Z';
perror <= fpgadone;
fault <= fpganinit;
fpga_epp_astrobe <= 'Z';
fpga_epp_dstrobe <= 'Z';
fpga_epp_read <= 'Z';
busy_wait <= para_wait;
usbwr <= '0';
usbnrd<= '1';
when usb =>
fpgaconfigd0 <= busd0;
if usbwritetsen = '1' and usb_echo = '1' then
if usblastd0 = '1' then
busd0 <= fpgadone;
else
busd0 <= FPGASize;
end if;
else
busd0 <= 'Z';
end if;
fpgancs_paramode <= '0';
fpganrdwr <= '0';
fpganprogram <= nreset;
cmcs <= 'Z';
cmdi <= 'Z';
perror <= 'Z';
fault <= 'Z';
fpga_epp_astrobe <= 'Z';
fpga_epp_dstrobe <= 'Z';
fpga_epp_read <= 'Z';
busy_wait <= 'Z';
usbwr <= usbconfigwrite;
usbnrd<= usbconfigread;
when spi =>
fpgaconfigd0 <= cmdo;
busd0 <= 'Z';
fpgancs_paramode <= '0';
fpganrdwr <= '0';
fpganprogram <= nreset and spi_program;
cmcs <= spi_cmcs;
cmdi <= spi_cmdi;
perror <= 'Z';
fault <= 'Z';
fpga_epp_astrobe <= 'Z';
fpga_epp_dstrobe <= 'Z';
fpga_epp_read <= 'Z';
busy_wait <= 'Z';
usbwr <= '0';
usbnrd<= '1';
when done =>
fpgaconfigd0 <= 'Z';
busd0 <= 'Z';
fpga_epp_astrobe <= selectin_astrobe;
fpga_epp_dstrobe <= autofd_dstrobe;
fpga_epp_read <= nstrobe_nwrite;
if fpgancs_paramode = '1' then -- FPGA says parallel mode so feed through
busy_wait <= fpga_epp_wait;
else
busy_wait <= 'Z';
end if;
fpgacclk <= 'Z';
fpgancs_paramode <= 'Z';
fpganrdwr <= 'Z';
fpganprogram <= nreset and fpganreconfig;
cmcs <= 'Z';
cmdi <= 'Z';
perror <= 'Z';
fault <= 'Z';
usbwr <= 'Z';
usbnrd<= 'Z';
end case;
end process;
end Behavioral;
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