library ieee;
use ieee.std_logic_1164.all;
use ieee.numeric_std.all;
library unisim;
use unisim.vcomponents.all;
library work;
use work.wishbone_types.all;
entity toplevel is
generic (
MEMORY_SIZE : integer := 16384;
RAM_INIT_FILE : string := "firmware.hex";
RESET_LOW : boolean := true;
CLK_FREQUENCY : positive := 100000000;
USE_LITEDRAM : boolean := false;
NO_BRAM : boolean := false;
DISABLE_FLATTEN_CORE : boolean := false
);
port(
ext_clk : in std_ulogic;
ext_rst : in std_ulogic;
-- UART0 signals:
uart_main_tx : out std_ulogic;
uart_main_rx : in std_ulogic;
-- DRAM UART signals (PMOD)
uart_pmod_tx : out std_ulogic;
uart_pmod_rx : in std_ulogic;
uart_pmod_cts_n : in std_ulogic;
uart_pmod_rts_n : out std_ulogic;
-- LEDs
led0_b : out std_ulogic;
led0_g : out std_ulogic;
led0_r : out std_ulogic;
-- DRAM wires
ddram_a : out std_ulogic_vector(13 downto 0);
ddram_ba : out std_ulogic_vector(2 downto 0);
ddram_ras_n : out std_ulogic;
ddram_cas_n : out std_ulogic;
ddram_we_n : out std_ulogic;
ddram_cs_n : out std_ulogic;
ddram_dm : out std_ulogic_vector(1 downto 0);
ddram_dq : inout std_ulogic_vector(15 downto 0);
ddram_dqs_p : inout std_ulogic_vector(1 downto 0);
ddram_dqs_n : inout std_ulogic_vector(1 downto 0);
ddram_clk_p : out std_ulogic;
ddram_clk_n : out std_ulogic;
ddram_cke : out std_ulogic;
ddram_odt : out std_ulogic;
ddram_reset_n : out std_ulogic
);
end entity toplevel;
architecture behaviour of toplevel is
-- Reset signals:
signal soc_rst : std_ulogic;
signal pll_rst : std_ulogic;
-- Internal clock signals:
signal system_clk : std_ulogic;
signal system_clk_locked : std_ulogic;
-- DRAM main data wishbone connection
signal wb_dram_in : wishbone_master_out;
signal wb_dram_out : wishbone_slave_out;
-- DRAM control wishbone connection
signal wb_dram_ctrl_in : wb_io_master_out;
signal wb_dram_ctrl_out : wb_io_slave_out;
signal wb_dram_is_csr : std_ulogic;
signal wb_dram_is_init : std_ulogic;
-- Control/status
signal core_alt_reset : std_ulogic;
-- Status LED
signal led0_b_pwm : std_ulogic;
signal led0_r_pwm : std_ulogic;
signal led0_g_pwm : std_ulogic;
-- Dumb PWM for the LEDs, those RGB LEDs are too bright otherwise
signal pwm_counter : std_ulogic_vector(8 downto 0);
-- Fixup various memory sizes based on generics
function get_bram_size return natural is
begin
if USE_LITEDRAM and NO_BRAM then
return 0;
else
return MEMORY_SIZE;
end if;
end function;
function get_payload_size return natural is
begin
if USE_LITEDRAM and NO_BRAM then
return MEMORY_SIZE;
else
return 0;
end if;
end function;
constant BRAM_SIZE : natural := get_bram_size;
constant PAYLOAD_SIZE : natural := get_payload_size;
begin
uart_pmod_rts_n <= '0';
-- Main SoC
soc0: entity work.soc
generic map(
MEMORY_SIZE => BRAM_SIZE,
RAM_INIT_FILE => RAM_INIT_FILE,
RESET_LOW => RESET_LOW,
SIM => false,
CLK_FREQ => CLK_FREQUENCY,
HAS_DRAM => USE_LITEDRAM,
DRAM_SIZE => 256 * 1024 * 1024,
DRAM_INIT_SIZE => PAYLOAD_SIZE,
DISABLE_FLATTEN_CORE => DISABLE_FLATTEN_CORE
)
port map (
system_clk => system_clk,
rst => soc_rst,
uart0_txd => uart_main_tx,
uart0_rxd => uart_main_rx,
wb_dram_in => wb_dram_in,
wb_dram_out => wb_dram_out,
wb_dram_ctrl_in => wb_dram_ctrl_in,
wb_dram_ctrl_out => wb_dram_ctrl_out,
wb_dram_is_csr => wb_dram_is_csr,
wb_dram_is_init => wb_dram_is_init,
alt_reset => core_alt_reset
);
nodram: if not USE_LITEDRAM generate
signal ddram_clk_dummy : std_ulogic;
begin
reset_controller: entity work.soc_reset
generic map(
RESET_LOW => RESET_LOW
)
port map(
ext_clk => ext_clk,
pll_clk => system_clk,
pll_locked_in => system_clk_locked,
ext_rst_in => ext_rst,
pll_rst_out => pll_rst,
rst_out => soc_rst
);
clkgen: entity work.clock_generator
generic map(
CLK_INPUT_HZ => 100000000,
CLK_OUTPUT_HZ => CLK_FREQUENCY
)
port map(
ext_clk => ext_clk,
pll_rst_in => pll_rst,
pll_clk_out => system_clk,
pll_locked_out => system_clk_locked
);
led0_b_pwm <= '1';
led0_r_pwm <= '1';
led0_g_pwm <= '0';
core_alt_reset <= '0';
-- Vivado barfs on those differential signals if left
-- unconnected. So instanciate a diff. buffer and feed
-- it a constant '0'.
dummy_dram_clk: OBUFDS
port map (
O => ddram_clk_p,
OB => ddram_clk_n,
I => ddram_clk_dummy
);
ddram_clk_dummy <= '0';
end generate;
has_dram: if USE_LITEDRAM generate
signal dram_init_done : std_ulogic;
signal dram_init_error : std_ulogic;
signal dram_sys_rst : std_ulogic;
begin
-- Eventually dig out the frequency from the generator
-- but for now, assert it's 100Mhz
assert CLK_FREQUENCY = 100000000;
reset_controller: entity work.soc_reset
generic map(
RESET_LOW => RESET_LOW,
PLL_RESET_BITS => 18,
SOC_RESET_BITS => 1
)
port map(
ext_clk => ext_clk,
pll_clk => system_clk,
pll_locked_in => '1',
ext_rst_in => ext_rst,
pll_rst_out => pll_rst,
rst_out => open
);
dram: entity work.litedram_wrapper
generic map(
DRAM_ABITS => 24,
DRAM_ALINES => 14,
PAYLOAD_FILE => RAM_INIT_FILE,
PAYLOAD_SIZE => PAYLOAD_SIZE
)
port map(
clk_in => ext_clk,
rst => pll_rst,
system_clk => system_clk,
system_reset => soc_rst,
core_alt_reset => core_alt_reset,
pll_locked => system_clk_locked,
wb_in => wb_dram_in,
wb_out => wb_dram_out,
wb_ctrl_in => wb_dram_ctrl_in,
wb_ctrl_out => wb_dram_ctrl_out,
wb_ctrl_is_csr => wb_dram_is_csr,
wb_ctrl_is_init => wb_dram_is_init,
serial_tx => uart_pmod_tx,
serial_rx => uart_pmod_rx,
init_done => dram_init_done,
init_error => dram_init_error,
ddram_a => ddram_a,
ddram_ba => ddram_ba,
ddram_ras_n => ddram_ras_n,
ddram_cas_n => ddram_cas_n,
ddram_we_n => ddram_we_n,
ddram_cs_n => ddram_cs_n,
ddram_dm => ddram_dm,
ddram_dq => ddram_dq,
ddram_dqs_p => ddram_dqs_p,
ddram_dqs_n => ddram_dqs_n,
ddram_clk_p => ddram_clk_p,
ddram_clk_n => ddram_clk_n,
ddram_cke => ddram_cke,
ddram_odt => ddram_odt,
ddram_reset_n => ddram_reset_n
);
led0_b_pwm <= not dram_init_done;
led0_r_pwm <= dram_init_error;
led0_g_pwm <= dram_init_done and not dram_init_error;
end generate;
leds_pwm : process(system_clk)
begin
if rising_edge(system_clk) then
pwm_counter <= std_ulogic_vector(signed(pwm_counter) + 1);
if pwm_counter(8 downto 4) = "00000" then
led0_b <= led0_b_pwm;
led0_r <= led0_r_pwm;
led0_g <= led0_g_pwm;
else
led0_b <= '0';
led0_r <= '0';
led0_g <= '0';
end if;
end if;
end process;
end architecture behaviour;