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nn-usb-fpga/plasma/logic/plasma.vhd
Carlos Camargo 22c469585b Adding plasma example
2010-04-21 20:01:38 -05:00

302 lines
11 KiB
VHDL
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---------------------------------------------------------------------
-- TITLE: Plasma (CPU core with memory)
-- AUTHOR: Steve Rhoads (rhoadss@yahoo.com)
-- DATE CREATED: 6/4/02
-- FILENAME: plasma.vhd
-- PROJECT: Plasma CPU core
-- COPYRIGHT: Software placed into the public domain by the author.
-- Software 'as is' without warranty. Author liable for nothing.
-- DESCRIPTION:
-- This entity combines the CPU core with memory and a UART.
--
-- Memory Map:
-- 0x00000000 - 0x0000ffff Internal RAM (8KB)
-- 0x10000000 - 0x100fffff External RAM (1MB)
-- Access all Misc registers with 32-bit accesses
-- 0x20000000 Uart Write (will pause CPU if busy)
-- 0x20000000 Uart Read
-- 0x20000010 IRQ Mask
-- 0x20000020 IRQ Status
-- 0x20000030 GPIO0 Out Set bits
-- 0x20000040 GPIO0 Out Clear bits
-- 0x20000050 GPIOA In
-- 0x20000060 Counter
-- 0x20000070 Ethernet transmit count
-- IRQ bits:
-- 7 GPIO31
-- 6 ^GPIO31
-- 5 EthernetSendDone
-- 4 EthernetReceive
-- 3 Counter(18)
-- 2 ^Counter(18)
-- 1 ^UartWriteBusy
-- 0 UartDataAvailable
---------------------------------------------------------------------
library ieee;
use ieee.std_logic_1164.all;
use work.mlite_pack.all;
entity plasma is
generic(memory_type : string := "XILINX_16X"; --"DUAL_PORT_" "ALTERA_LPM";
log_file : string := "UNUSED";
ethernet : std_logic := '0';
use_cache : std_logic := '0');
port(clk : in std_logic;
reset : in std_logic;
uart_write : out std_logic;
uart_read : in std_logic;
address : out std_logic_vector(31 downto 2);
byte_we : out std_logic_vector(3 downto 0);
data_write : out std_logic_vector(31 downto 0);
data_read : in std_logic_vector(31 downto 0);
mem_pause_in : in std_logic;
no_ddr_start : out std_logic;
no_ddr_stop : out std_logic;
gpio0_out : out std_logic_vector(31 downto 0);
gpioA_in : in std_logic_vector(31 downto 0));
end; --entity plasma
architecture logic of plasma is
signal address_next : std_logic_vector(31 downto 2);
signal byte_we_next : std_logic_vector(3 downto 0);
signal cpu_address : std_logic_vector(31 downto 0);
signal cpu_byte_we : std_logic_vector(3 downto 0);
signal cpu_data_w : std_logic_vector(31 downto 0);
signal cpu_data_r : std_logic_vector(31 downto 0);
signal cpu_pause : std_logic;
signal data_read_uart : std_logic_vector(7 downto 0);
signal write_enable : std_logic;
signal eth_pause_in : std_logic;
signal eth_pause : std_logic;
signal mem_busy : std_logic;
signal enable_misc : std_logic;
signal enable_uart : std_logic;
signal enable_uart_read : std_logic;
signal enable_uart_write : std_logic;
signal enable_eth : std_logic;
signal gpio0_reg : std_logic_vector(31 downto 0);
signal uart_write_busy : std_logic;
signal uart_data_avail : std_logic;
signal irq_mask_reg : std_logic_vector(7 downto 0);
signal irq_status : std_logic_vector(7 downto 0);
signal irq : std_logic;
signal irq_eth_rec : std_logic;
signal irq_eth_send : std_logic;
signal counter_reg : std_logic_vector(31 downto 0);
signal ram_enable : std_logic;
signal ram_byte_we : std_logic_vector(3 downto 0);
signal ram_address : std_logic_vector(31 downto 2);
signal ram_data_w : std_logic_vector(31 downto 0);
signal ram_data_r : std_logic_vector(31 downto 0);
signal cache_check : std_logic;
signal cache_checking : std_logic;
signal cache_miss : std_logic;
signal cache_hit : std_logic;
begin --architecture
write_enable <= '1' when cpu_byte_we /= "0000" else '0';
mem_busy <= eth_pause or mem_pause_in;
cache_hit <= cache_checking and not cache_miss;
cpu_pause <= (uart_write_busy and enable_uart and write_enable) or --UART busy
cache_miss or --Cache wait
(cpu_address(28) and not cache_hit and mem_busy); --DDR or flash --DDR in use
irq_status <= gpioA_in(31) & not gpioA_in(31) &
irq_eth_send & irq_eth_rec &
counter_reg(18) & not counter_reg(18) &
not uart_write_busy & uart_data_avail;
irq <= '1' when (irq_status and irq_mask_reg) /= ZERO(7 downto 0) else '0';
gpio0_out(31 downto 29) <= gpio0_reg(31 downto 29);
gpio0_out(23 downto 0) <= gpio0_reg(23 downto 0);
enable_misc <= '1' when cpu_address(30 downto 28) = "010" else '0';
enable_uart <= '1' when enable_misc = '1' and cpu_address(7 downto 4) = "0000" else '0';
enable_uart_read <= enable_uart and not write_enable;
enable_uart_write <= enable_uart and write_enable;
enable_eth <= '1' when enable_misc = '1' and cpu_address(7 downto 4) = "0111" else '0';
cpu_address(1 downto 0) <= "00";
u1_cpu: mlite_cpu
generic map (memory_type => memory_type)
PORT MAP (
clk => clk,
reset_in => reset,
intr_in => irq,
address_next => address_next, --before rising_edge(clk)
byte_we_next => byte_we_next,
address => cpu_address(31 downto 2), --after rising_edge(clk)
byte_we => cpu_byte_we,
data_w => cpu_data_w,
data_r => cpu_data_r,
mem_pause => cpu_pause);
opt_cache: if use_cache = '0' generate
cache_check <= '0';
cache_checking <= '0';
cache_miss <= '0';
end generate;
opt_cache2: if use_cache = '1' generate
--Control 4KB unified cache that uses the upper 4KB of the 8KB
--internal RAM. Only lowest 2MB of DDR is cached.
u_cache: cache
generic map (memory_type => memory_type)
PORT MAP (
clk => clk,
reset => reset,
address_next => address_next,
byte_we_next => byte_we_next,
cpu_address => cpu_address(31 downto 2),
mem_busy => mem_busy,
cache_check => cache_check, --Stage1: address_next in first 2MB DDR
cache_checking => cache_checking, --Stage2
cache_miss => cache_miss); --Stage3
end generate; --opt_cache2
no_ddr_start <= not eth_pause and cache_checking;
no_ddr_stop <= not eth_pause and cache_miss;
eth_pause_in <= mem_pause_in or (not eth_pause and cache_miss and not cache_checking);
misc_proc: process(clk, reset, cpu_address, enable_misc,
ram_data_r, data_read, data_read_uart, cpu_pause,
irq_mask_reg, irq_status, gpio0_reg, write_enable,
cache_checking,
gpioA_in, counter_reg, cpu_data_w)
begin
case cpu_address(30 downto 28) is
when "000" => --internal RAM
cpu_data_r <= ram_data_r;
when "001" => --external RAM
if cache_checking = '1' then
cpu_data_r <= ram_data_r; --cache
else
cpu_data_r <= data_read; --DDR
end if;
when "010" => --misc
case cpu_address(6 downto 4) is
when "000" => --uart
cpu_data_r <= ZERO(31 downto 8) & data_read_uart;
when "001" => --irq_mask
cpu_data_r <= ZERO(31 downto 8) & irq_mask_reg;
when "010" => --irq_status
cpu_data_r <= ZERO(31 downto 8) & irq_status;
when "011" => --gpio0
cpu_data_r <= gpio0_reg;
when "101" => --gpioA
cpu_data_r <= gpioA_in;
when "110" => --counter
cpu_data_r <= counter_reg;
when others =>
cpu_data_r <= gpioA_in;
end case;
when "011" => --flash
cpu_data_r <= data_read;
when others =>
cpu_data_r <= ZERO;
end case;
if reset = '1' then
irq_mask_reg <= ZERO(7 downto 0);
gpio0_reg <= ZERO;
counter_reg <= ZERO;
elsif rising_edge(clk) then
if cpu_pause = '0' then
if enable_misc = '1' and write_enable = '1' then
if cpu_address(6 downto 4) = "001" then
irq_mask_reg <= cpu_data_w(7 downto 0);
elsif cpu_address(6 downto 4) = "011" then
gpio0_reg <= gpio0_reg or cpu_data_w;
elsif cpu_address(6 downto 4) = "100" then
gpio0_reg <= gpio0_reg and not cpu_data_w;
end if;
end if;
end if;
counter_reg <= bv_inc(counter_reg);
end if;
end process;
ram_enable <= '1' when address_next(30 downto 28) = "000" or
cache_check = '1' or cache_miss = '1' else '0';
ram_byte_we <= byte_we_next when cache_miss = '0' else "1111";
ram_address(31 downto 13) <= ZERO(31 downto 13);
ram_address(12 downto 2) <= (address_next(12) or cache_check) & address_next(11 downto 2)
when cache_miss = '0' else
'1' & cpu_address(11 downto 2); --Update cache after cache miss
ram_data_w <= cpu_data_w when cache_miss = '0' else data_read;
u2_ram: ram
generic map (memory_type => memory_type)
port map (
clk => clk,
enable => ram_enable,
write_byte_enable => ram_byte_we,
address => ram_address,
data_write => ram_data_w,
data_read => ram_data_r);
u3_uart: uart
generic map (log_file => log_file)
port map(
clk => clk,
reset => reset,
enable_read => enable_uart_read,
enable_write => enable_uart_write,
data_in => cpu_data_w(7 downto 0),
data_out => data_read_uart,
uart_read => uart_read,
uart_write => uart_write,
busy_write => uart_write_busy,
data_avail => uart_data_avail);
dma_gen: if ethernet = '0' generate
address <= cpu_address(31 downto 2);
byte_we <= cpu_byte_we;
data_write <= cpu_data_w;
eth_pause <= '0';
gpio0_out(28 downto 24) <= ZERO(28 downto 24);
irq_eth_rec <= '0';
irq_eth_send <= '0';
end generate;
dma_gen2: if ethernet = '1' generate
u4_eth: eth_dma
port map(
clk => clk,
reset => reset,
enable_eth => gpio0_reg(24),
select_eth => enable_eth,
rec_isr => irq_eth_rec,
send_isr => irq_eth_send,
address => address, --to DDR
byte_we => byte_we,
data_write => data_write,
data_read => data_read,
pause_in => eth_pause_in,
mem_address => cpu_address(31 downto 2), --from CPU
mem_byte_we => cpu_byte_we,
data_w => cpu_data_w,
pause_out => eth_pause,
E_RX_CLK => gpioA_in(20),
E_RX_DV => gpioA_in(19),
E_RXD => gpioA_in(18 downto 15),
E_TX_CLK => gpioA_in(14),
E_TX_EN => gpio0_out(28),
E_TXD => gpio0_out(27 downto 24));
end generate;
end; --architecture logic
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