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  • This comparison shows the changes necessary to convert path 
    /neo430/trunk/neo430/rtl/fpga_specific/lattice_ice40up
    from Rev 198 to Rev 199
    ↔ Reverse comparison
  •

Rev 198 → Rev 199

/neo430_imem.ice40up_spram.vhd
67,6 → 67,10
 
architecture neo430_imem_rtl of neo430_imem is
 
-- advanced configuration ------------------------------------------------------------------------------------
constant spram_sleep_mode_en_c : boolean := false; -- put IMEM into sleep mode when idle (for low power)
-- -------------------------------------------------------------------------------------------------------
 
-- ROM types --
type imem_file8_t is array (0 to IMEM_SIZE/2-1) of std_ulogic_vector(07 downto 0);
 
85,10 → 89,12
end function init_imem;
 
-- local signals --
signal acc_en : std_ulogic;
signal rdata : std_ulogic_vector(15 downto 0);
signal rden : std_ulogic;
signal addr : integer;
signal acc_en : std_ulogic;
signal mem_cs : std_ulogic;
signal rdata : std_ulogic_vector(15 downto 0);
signal rden : std_ulogic;
signal mem_sel : std_ulogic;
signal addr : integer;
 
-- internal "RAM" type - implemented if bootloader is used and IMEM is RAM and initialized with app code --
signal imem_file_init_ram_l : imem_file8_t := init_imem('0', application_init_image);
117,12 → 123,15
attribute syn_ramstyle of imem_file_ram_h : signal is "no_rw_check";
 
-- SPRAM signals --
signal spram_clk : std_logic;
signal spram_addr : std_logic_vector(13 downto 0);
signal spram_di : std_logic_vector(15 downto 0);
signal spram_do : std_logic_vector(15 downto 0);
signal spram_be : std_logic_vector(03 downto 0);
signal spram_we : std_logic;
signal spram_clk : std_logic;
signal spram_addr : std_logic_vector(13 downto 0);
signal spram_di : std_logic_vector(15 downto 0);
signal spram_do_lo : std_logic_vector(15 downto 0);
signal spram_do_hi : std_logic_vector(15 downto 0);
signal spram_be : std_logic_vector(03 downto 0);
signal spram_we : std_logic;
signal spram_pwr_n : std_logic;
signal spram_cs : std_logic_vector(01 downto 0);
 
begin
 
130,6 → 139,7
-- -----------------------------------------------------------------------------
acc_en <= '1' when (addr_i >= imem_base_c) and (addr_i < std_ulogic_vector(unsigned(imem_base_c) + IMEM_SIZE)) else '0';
addr <= to_integer(unsigned(addr_i(index_size_f(IMEM_SIZE/2) downto 1))); -- word aligned
mem_cs <= acc_en and (rden_i or wren_i(1) or wren_i(0));
 
 
-- Memory Access ------------------------------------------------------------
137,27 → 147,49
imem_spram_lo_inst : SP256K
port map (
AD => spram_addr, -- I
DI => spram_di, -- I
MASKWE => spram_be, -- I
WE => spram_we, -- I
CS => '1', -- I
CK => spram_clk, -- I
STDBY => '0', -- I
SLEEP => '0', -- I
PWROFF_N => '1', -- I
DO => spram_do -- O
DI => spram_di, -- I
MASKWE => spram_be, -- I
WE => spram_we, -- I
CS => spram_cs(0), -- I
CK => spram_clk, -- I
STDBY => '0', -- I
SLEEP => spram_pwr_n, -- I
PWROFF_N => '1', -- I
DO => spram_do_lo -- O
);
 
-- signal type conversion --
spram_clk <= std_logic(clk_i);
spram_addr <= std_logic_vector(addr_i(13+1 downto 0+1));
spram_di <= std_logic_vector(data_i(15 downto 0));
spram_we <= '1' when ((acc_en and upen_i and (wren_i(0) or wren_i(1))) = '1') else '0'; -- global write enable
rdata <= std_ulogic_vector(spram_do);
-- instantiate second SPRAM if IMEM size > 32kB --
imem_spram_hi_bank:
if (IMEM_SIZE > 32*1024) generate
imem_spram_hi_inst : SP256K
port map (
AD => spram_addr, -- I
DI => spram_di, -- I
MASKWE => spram_be, -- I
WE => spram_we, -- I
CS => spram_cs(1), -- I
CK => spram_clk, -- I
STDBY => '0', -- I
SLEEP => spram_pwr_n, -- I
PWROFF_N => '1', -- I
DO => spram_do_hi -- O
);
end generate;
 
-- access logic and signal type conversion --
spram_clk <= std_logic(clk_i);
spram_addr <= std_logic_vector(addr_i(13+1 downto 0+1));
spram_di <= std_logic_vector(data_i(15 downto 0));
spram_we <= '1' when ((acc_en and upen_i and (wren_i(0) or wren_i(1))) = '1') else '0'; -- global write enable
rdata <= std_ulogic_vector(spram_do_lo) when (mem_sel = '0') else std_ulogic_vector(spram_do_hi); -- lo/hi memory bank
spram_cs(0) <= '1' when (addr_i(15) = '0') else '0'; -- low memory bank
spram_cs(1) <= '1' when (addr_i(15) = '1') else '0'; -- high memory bank
 
spram_be(1 downto 0) <= "11" when (wren_i(0) = '1') else "00"; -- low byte write enable
spram_be(3 downto 2) <= "11" when (wren_i(1) = '1') else "00"; -- high byte write enable
 
spram_pwr_n <= '0' when ((spram_sleep_mode_en_c = false) or (mem_cs = '1')) else '1'; -- LP mode disabled or IMEM selected
 
buffer_ff: process(clk_i)
begin
-- sanity check --
164,12 → 196,13
if (IMEM_AS_ROM = true) or (BOOTLD_USE = false) then
assert false report "ICE40 Ultra Plus SPRAM cannot be initialized by bitstream!" severity error;
end if;
if (IMEM_SIZE > 32*1024) then
assert false report "I-mem size out of range! Max 32kB!" severity error;
if (IMEM_SIZE > 48*1024) then
assert false report "I-mem size out of range! Max 48kB!" severity error;
end if;
-- buffer --
if rising_edge(clk_i) then
rden <= rden_i and acc_en;
mem_sel <= addr_i(15);
rden <= rden_i and acc_en;
end if;
end process buffer_ff;
 

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