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;
HAS_FPU : boolean := true;
HAS_BTC : boolean := true;
USE_LITEDRAM : boolean := false;
NO_BRAM : boolean := false;
DISABLE_FLATTEN_CORE : boolean := false;
SCLK_STARTUPE2 : boolean := false;
SPI_FLASH_OFFSET : integer := 4194304;
SPI_FLASH_DEF_CKDV : natural := 1;
SPI_FLASH_DEF_QUAD : boolean := true;
LOG_LENGTH : natural := 512;
USE_LITEETH : boolean := false;
UART_IS_16550 : boolean := false;
HAS_UART1 : boolean := true;
USE_LITESDCARD : boolean := false;
NGPIO : natural := 32
);
port(
ext_clk : in std_ulogic;
ext_rst_n : in std_ulogic;
-- UART0 signals:
uart_main_tx : out std_ulogic;
uart_main_rx : in std_ulogic;
-- LEDs
led0_b : out std_ulogic;
led0_g : out std_ulogic;
led0_r : out std_ulogic;
led4 : out std_ulogic;
led5 : out std_ulogic;
led6 : out std_ulogic;
led7 : out std_ulogic;
-- SPI
spi_flash_cs_n : out std_ulogic;
spi_flash_clk : out std_ulogic;
spi_flash_mosi : inout std_ulogic;
spi_flash_miso : inout std_ulogic;
spi_flash_wp_n : inout std_ulogic;
spi_flash_hold_n : inout std_ulogic;
-- GPIO
shield_io : inout std_ulogic_vector(44 downto 0);
-- Ethernet
eth_ref_clk : out std_ulogic;
eth_clocks_tx : in std_ulogic;
eth_clocks_rx : in std_ulogic;
eth_rst_n : out std_ulogic;
eth_mdio : inout std_ulogic;
eth_mdc : out std_ulogic;
eth_rx_dv : in std_ulogic;
eth_rx_er : in std_ulogic;
eth_rx_data : in std_ulogic_vector(3 downto 0);
eth_tx_en : out std_ulogic;
eth_tx_data : out std_ulogic_vector(3 downto 0);
eth_col : in std_ulogic;
eth_crs : in std_ulogic;
-- SD card
sdcard_data : inout std_ulogic_vector(3 downto 0);
sdcard_cmd : inout std_ulogic;
sdcard_clk : out std_ulogic;
sdcard_cd : in 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;
signal eth_clk_locked : std_ulogic;
-- External IOs from the SoC
signal wb_ext_io_in : wb_io_master_out;
signal wb_ext_io_out : wb_io_slave_out;
signal wb_ext_is_dram_csr : std_ulogic;
signal wb_ext_is_dram_init : std_ulogic;
signal wb_ext_is_eth : std_ulogic;
signal wb_ext_is_sdcard : 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_out : wb_io_slave_out := wb_io_slave_out_init;
-- LiteEth connection
signal ext_irq_eth : std_ulogic;
signal wb_eth_out : wb_io_slave_out := wb_io_slave_out_init;
-- LiteSDCard connection
signal ext_irq_sdcard : std_ulogic := '0';
signal wb_sdcard_out : wb_io_slave_out := wb_io_slave_out_init;
signal wb_sddma_out : wb_io_master_out := wb_io_master_out_init;
signal wb_sddma_in : wb_io_slave_out;
signal wb_sddma_nr : wb_io_master_out;
signal wb_sddma_ir : wb_io_slave_out;
-- for conversion from non-pipelined wishbone to pipelined
signal wb_sddma_stb_sent : 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);
-- SPI flash
signal spi_sck : std_ulogic;
signal spi_cs_n : std_ulogic;
signal spi_sdat_o : std_ulogic_vector(3 downto 0);
signal spi_sdat_oe : std_ulogic_vector(3 downto 0);
signal spi_sdat_i : std_ulogic_vector(3 downto 0);
-- GPIO
signal gpio_in : std_ulogic_vector(NGPIO - 1 downto 0);
signal gpio_out : std_ulogic_vector(NGPIO - 1 downto 0);
signal gpio_dir : std_ulogic_vector(NGPIO - 1 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
-- Main SoC
soc0: entity work.soc
generic map(
MEMORY_SIZE => BRAM_SIZE,
RAM_INIT_FILE => RAM_INIT_FILE,
SIM => false,
CLK_FREQ => CLK_FREQUENCY,
HAS_FPU => HAS_FPU,
HAS_BTC => HAS_BTC,
HAS_DRAM => USE_LITEDRAM,
DRAM_SIZE => 256 * 1024 * 1024,
DRAM_INIT_SIZE => PAYLOAD_SIZE,
DISABLE_FLATTEN_CORE => DISABLE_FLATTEN_CORE,
HAS_SPI_FLASH => true,
SPI_FLASH_DLINES => 4,
SPI_FLASH_OFFSET => SPI_FLASH_OFFSET,
SPI_FLASH_DEF_CKDV => SPI_FLASH_DEF_CKDV,
SPI_FLASH_DEF_QUAD => SPI_FLASH_DEF_QUAD,
LOG_LENGTH => LOG_LENGTH,
HAS_LITEETH => USE_LITEETH,
UART0_IS_16550 => UART_IS_16550,
HAS_UART1 => HAS_UART1,
HAS_SD_CARD => USE_LITESDCARD,
NGPIO => NGPIO
)
port map (
-- System signals
system_clk => system_clk,
rst => soc_rst,
-- UART signals
uart0_txd => uart_main_tx,
uart0_rxd => uart_main_rx,
-- UART1 signals
--uart1_txd => uart_pmod_tx,
--uart1_rxd => uart_pmod_rx,
-- SPI signals
spi_flash_sck => spi_sck,
spi_flash_cs_n => spi_cs_n,
spi_flash_sdat_o => spi_sdat_o,
spi_flash_sdat_oe => spi_sdat_oe,
spi_flash_sdat_i => spi_sdat_i,
-- GPIO signals
gpio_in => gpio_in,
gpio_out => gpio_out,
gpio_dir => gpio_dir,
-- External interrupts
ext_irq_eth => ext_irq_eth,
ext_irq_sdcard => ext_irq_sdcard,
-- DRAM wishbone
wb_dram_in => wb_dram_in,
wb_dram_out => wb_dram_out,
-- IO wishbone
wb_ext_io_in => wb_ext_io_in,
wb_ext_io_out => wb_ext_io_out,
wb_ext_is_dram_csr => wb_ext_is_dram_csr,
wb_ext_is_dram_init => wb_ext_is_dram_init,
wb_ext_is_eth => wb_ext_is_eth,
wb_ext_is_sdcard => wb_ext_is_sdcard,
-- DMA wishbone
wishbone_dma_in => wb_sddma_in,
wishbone_dma_out => wb_sddma_out,
alt_reset => core_alt_reset
);
--uart_pmod_rts_n <= '0';
-- SPI Flash
--
-- Note: Unlike many other boards, the SPI flash on the Arty has
-- an actual pin to generate the clock and doesn't require to use
-- the STARTUPE2 primitive.
--
spi_flash_cs_n <= spi_cs_n;
spi_flash_mosi <= spi_sdat_o(0) when spi_sdat_oe(0) = '1' else 'Z';
spi_flash_miso <= spi_sdat_o(1) when spi_sdat_oe(1) = '1' else 'Z';
spi_flash_wp_n <= spi_sdat_o(2) when spi_sdat_oe(2) = '1' else 'Z';
spi_flash_hold_n <= spi_sdat_o(3) when spi_sdat_oe(3) = '1' else 'Z';
spi_sdat_i(0) <= spi_flash_mosi;
spi_sdat_i(1) <= spi_flash_miso;
spi_sdat_i(2) <= spi_flash_wp_n;
spi_sdat_i(3) <= spi_flash_hold_n;
spi_sclk_startupe2: if SCLK_STARTUPE2 generate
spi_flash_clk <= 'Z';
STARTUPE2_INST: STARTUPE2
port map (
CLK => '0',
GSR => '0',
GTS => '0',
KEYCLEARB => '0',
PACK => '0',
USRCCLKO => spi_sck,
USRCCLKTS => '0',
USRDONEO => '1',
USRDONETS => '0'
);
end generate;
spi_direct_sclk: if not SCLK_STARTUPE2 generate
spi_flash_clk <= spi_sck;
end generate;
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 and eth_clk_locked,
ext_rst_in => ext_rst_n,
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;
signal rst_gen_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 => eth_clk_locked,
ext_rst_in => ext_rst_n,
pll_rst_out => pll_rst,
rst_out => rst_gen_rst
);
-- Generate SoC reset
soc_rst_gen: process(system_clk)
begin
if ext_rst_n = '0' then
soc_rst <= '1';
elsif rising_edge(system_clk) then
soc_rst <= dram_sys_rst or not eth_clk_locked or not system_clk_locked;
end if;
end process;
dram: entity work.litedram_wrapper
generic map(
DRAM_ABITS => 24,
DRAM_ALINES => 14,
DRAM_DLINES => 16,
DRAM_PORT_WIDTH => 128,
PAYLOAD_FILE => RAM_INIT_FILE,
PAYLOAD_SIZE => PAYLOAD_SIZE
)
port map(
clk_in => ext_clk,
rst => pll_rst,
system_clk => system_clk,
system_reset => dram_sys_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_ext_io_in,
wb_ctrl_out => wb_dram_ctrl_out,
wb_ctrl_is_csr => wb_ext_is_dram_csr,
wb_ctrl_is_init => wb_ext_is_dram_init,
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;
has_liteeth : if USE_LITEETH generate
component liteeth_core port (
sys_clock : in std_ulogic;
sys_reset : in std_ulogic;
mii_eth_clocks_tx : in std_ulogic;
mii_eth_clocks_rx : in std_ulogic;
mii_eth_rst_n : out std_ulogic;
mii_eth_mdio : in std_ulogic;
mii_eth_mdc : out std_ulogic;
mii_eth_rx_dv : in std_ulogic;
mii_eth_rx_er : in std_ulogic;
mii_eth_rx_data : in std_ulogic_vector(3 downto 0);
mii_eth_tx_en : out std_ulogic;
mii_eth_tx_data : out std_ulogic_vector(3 downto 0);
mii_eth_col : in std_ulogic;
mii_eth_crs : in std_ulogic;
wishbone_adr : in std_ulogic_vector(29 downto 0);
wishbone_dat_w : in std_ulogic_vector(31 downto 0);
wishbone_dat_r : out std_ulogic_vector(31 downto 0);
wishbone_sel : in std_ulogic_vector(3 downto 0);
wishbone_cyc : in std_ulogic;
wishbone_stb : in std_ulogic;
wishbone_ack : out std_ulogic;
wishbone_we : in std_ulogic;
wishbone_cti : in std_ulogic_vector(2 downto 0);
wishbone_bte : in std_ulogic_vector(1 downto 0);
wishbone_err : out std_ulogic;
interrupt : out std_ulogic
);
end component;
signal wb_eth_cyc : std_ulogic;
signal wb_eth_adr : std_ulogic_vector(29 downto 0);
-- Change this to use a PLL instead of a BUFR to generate the 25Mhz
-- reference clock to the PHY.
constant USE_PLL : boolean := false;
begin
eth_use_pll: if USE_PLL generate
signal eth_clk_25 : std_ulogic;
signal eth_clkfb : std_ulogic;
begin
pll_eth : PLLE2_BASE
generic map (
BANDWIDTH => "OPTIMIZED",
CLKFBOUT_MULT => 16,
CLKIN1_PERIOD => 10.0,
CLKOUT0_DIVIDE => 64,
DIVCLK_DIVIDE => 1,
STARTUP_WAIT => "FALSE")
port map (
CLKOUT0 => eth_clk_25,
CLKOUT1 => open,
CLKOUT2 => open,
CLKOUT3 => open,
CLKOUT4 => open,
CLKOUT5 => open,
CLKFBOUT => eth_clkfb,
LOCKED => eth_clk_locked,
CLKIN1 => ext_clk,
PWRDWN => '0',
RST => pll_rst,
CLKFBIN => eth_clkfb);
eth_clk_buf: BUFG
port map (
I => eth_clk_25,
O => eth_ref_clk
);
end generate;
eth_use_bufr: if not USE_PLL generate
eth_clk_div: BUFR
generic map (
BUFR_DIVIDE => "4"
)
port map (
I => system_clk,
O => eth_ref_clk,
CE => '1',
CLR => '0'
);
eth_clk_locked <= '1';
end generate;
liteeth : liteeth_core
port map(
sys_clock => system_clk,
sys_reset => soc_rst,
mii_eth_clocks_tx => eth_clocks_tx,
mii_eth_clocks_rx => eth_clocks_rx,
mii_eth_rst_n => eth_rst_n,
mii_eth_mdio => eth_mdio,
mii_eth_mdc => eth_mdc,
mii_eth_rx_dv => eth_rx_dv,
mii_eth_rx_er => eth_rx_er,
mii_eth_rx_data => eth_rx_data,
mii_eth_tx_en => eth_tx_en,
mii_eth_tx_data => eth_tx_data,
mii_eth_col => eth_col,
mii_eth_crs => eth_crs,
wishbone_adr => wb_eth_adr,
wishbone_dat_w => wb_ext_io_in.dat,
wishbone_dat_r => wb_eth_out.dat,
wishbone_sel => wb_ext_io_in.sel,
wishbone_cyc => wb_eth_cyc,
wishbone_stb => wb_ext_io_in.stb,
wishbone_ack => wb_eth_out.ack,
wishbone_we => wb_ext_io_in.we,
wishbone_cti => "000",
wishbone_bte => "00",
wishbone_err => open,
interrupt => ext_irq_eth
);
-- Gate cyc with "chip select" from soc
wb_eth_cyc <= wb_ext_io_in.cyc and wb_ext_is_eth;
-- Remove top address bits as liteeth decoder doesn't know about them
wb_eth_adr <= x"000" & "000" & wb_ext_io_in.adr(16 downto 2);
-- LiteETH isn't pipelined
wb_eth_out.stall <= not wb_eth_out.ack;
end generate;
no_liteeth : if not USE_LITEETH generate
eth_clk_locked <= '1';
ext_irq_eth <= '0';
end generate;
-- SD card pmod
has_sdcard : if USE_LITESDCARD generate
component litesdcard_core port (
clk : in std_ulogic;
rst : in std_ulogic;
-- wishbone for accessing control registers
wb_ctrl_adr : in std_ulogic_vector(29 downto 0);
wb_ctrl_dat_w : in std_ulogic_vector(31 downto 0);
wb_ctrl_dat_r : out std_ulogic_vector(31 downto 0);
wb_ctrl_sel : in std_ulogic_vector(3 downto 0);
wb_ctrl_cyc : in std_ulogic;
wb_ctrl_stb : in std_ulogic;
wb_ctrl_ack : out std_ulogic;
wb_ctrl_we : in std_ulogic;
wb_ctrl_cti : in std_ulogic_vector(2 downto 0);
wb_ctrl_bte : in std_ulogic_vector(1 downto 0);
wb_ctrl_err : out std_ulogic;
-- wishbone for SD card core to use for DMA
wb_dma_adr : out std_ulogic_vector(29 downto 0);
wb_dma_dat_w : out std_ulogic_vector(31 downto 0);
wb_dma_dat_r : in std_ulogic_vector(31 downto 0);
wb_dma_sel : out std_ulogic_vector(3 downto 0);
wb_dma_cyc : out std_ulogic;
wb_dma_stb : out std_ulogic;
wb_dma_ack : in std_ulogic;
wb_dma_we : out std_ulogic;
wb_dma_cti : out std_ulogic_vector(2 downto 0);
wb_dma_bte : out std_ulogic_vector(1 downto 0);
wb_dma_err : in std_ulogic;
-- connections to SD card
sdcard_data : inout std_ulogic_vector(3 downto 0);
sdcard_cmd : inout std_ulogic;
sdcard_clk : out std_ulogic;
sdcard_cd : in std_ulogic;
irq : out std_ulogic
);
end component;
signal wb_sdcard_cyc : std_ulogic;
signal wb_sdcard_adr : std_ulogic_vector(29 downto 0);
begin
litesdcard : litesdcard_core
port map (
clk => system_clk,
rst => soc_rst,
wb_ctrl_adr => wb_sdcard_adr,
wb_ctrl_dat_w => wb_ext_io_in.dat,
wb_ctrl_dat_r => wb_sdcard_out.dat,
wb_ctrl_sel => wb_ext_io_in.sel,
wb_ctrl_cyc => wb_sdcard_cyc,
wb_ctrl_stb => wb_ext_io_in.stb,
wb_ctrl_ack => wb_sdcard_out.ack,
wb_ctrl_we => wb_ext_io_in.we,
wb_ctrl_cti => "000",
wb_ctrl_bte => "00",
wb_ctrl_err => open,
wb_dma_adr => wb_sddma_nr.adr,
wb_dma_dat_w => wb_sddma_nr.dat,
wb_dma_dat_r => wb_sddma_ir.dat,
wb_dma_sel => wb_sddma_nr.sel,
wb_dma_cyc => wb_sddma_nr.cyc,
wb_dma_stb => wb_sddma_nr.stb,
wb_dma_ack => wb_sddma_ir.ack,
wb_dma_we => wb_sddma_nr.we,
wb_dma_cti => open,
wb_dma_bte => open,
wb_dma_err => '0',
sdcard_data => sdcard_data,
sdcard_cmd => sdcard_cmd,
sdcard_clk => sdcard_clk,
sdcard_cd => sdcard_cd,
irq => ext_irq_sdcard
);
-- Gate cyc with chip select from SoC
wb_sdcard_cyc <= wb_ext_io_in.cyc and wb_ext_is_sdcard;
wb_sdcard_adr <= x"0000" & wb_ext_io_in.adr(15 downto 2);
wb_sdcard_out.stall <= not wb_sdcard_out.ack;
-- Convert non-pipelined DMA wishbone to pipelined by suppressing
-- non-acknowledged strobes
process(system_clk)
begin
if rising_edge(system_clk) then
wb_sddma_out <= wb_sddma_nr;
if wb_sddma_stb_sent = '1' or
(wb_sddma_out.stb = '1' and wb_sddma_in.stall = '0') then
wb_sddma_out.stb <= '0';
end if;
if wb_sddma_nr.cyc = '0' or wb_sddma_ir.ack = '1' then
wb_sddma_stb_sent <= '0';
elsif wb_sddma_in.stall = '0' then
wb_sddma_stb_sent <= wb_sddma_nr.stb;
end if;
wb_sddma_ir <= wb_sddma_in;
end if;
end process;
end generate;
-- Mux WB response on the IO bus
wb_ext_io_out <= wb_eth_out when wb_ext_is_eth = '1' else
wb_sdcard_out when wb_ext_is_sdcard = '1' else
wb_dram_ctrl_out;
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;
led4 <= system_clk_locked;
led5 <= eth_clk_locked;
led6 <= not soc_rst;
-- GPIO
gpio_in(0) <= shield_io(0);
gpio_in(1) <= shield_io(1);
gpio_in(2) <= shield_io(2);
gpio_in(3) <= shield_io(3);
gpio_in(4) <= shield_io(4);
gpio_in(5) <= shield_io(5);
gpio_in(6) <= shield_io(6);
gpio_in(7) <= shield_io(7);
gpio_in(8) <= shield_io(8);
gpio_in(9) <= shield_io(9);
gpio_in(10) <= shield_io(10);
gpio_in(11) <= shield_io(11);
gpio_in(12) <= shield_io(12);
gpio_in(13) <= shield_io(13);
gpio_in(14) <= shield_io(26);
gpio_in(15) <= shield_io(27);
gpio_in(16) <= shield_io(28);
gpio_in(17) <= shield_io(29);
gpio_in(18) <= shield_io(30);
gpio_in(19) <= shield_io(31);
gpio_in(20) <= shield_io(32);
gpio_in(21) <= shield_io(33);
gpio_in(22) <= shield_io(34);
gpio_in(23) <= shield_io(35);
gpio_in(24) <= shield_io(36);
gpio_in(25) <= shield_io(37);
gpio_in(26) <= shield_io(38);
gpio_in(27) <= shield_io(39);
gpio_in(28) <= shield_io(40);
gpio_in(29) <= shield_io(41);
gpio_in(30) <= shield_io(43);
gpio_in(31) <= shield_io(44);
shield_io(0) <= gpio_out(0) when gpio_dir(0) = '1' else 'Z';
shield_io(1) <= gpio_out(1) when gpio_dir(1) = '1' else 'Z';
shield_io(2) <= gpio_out(2) when gpio_dir(2) = '1' else 'Z';
shield_io(3) <= gpio_out(3) when gpio_dir(3) = '1' else 'Z';
shield_io(4) <= gpio_out(4) when gpio_dir(4) = '1' else 'Z';
shield_io(5) <= gpio_out(5) when gpio_dir(5) = '1' else 'Z';
shield_io(6) <= gpio_out(6) when gpio_dir(6) = '1' else 'Z';
shield_io(7) <= gpio_out(7) when gpio_dir(7) = '1' else 'Z';
shield_io(8) <= gpio_out(8) when gpio_dir(8) = '1' else 'Z';
shield_io(9) <= gpio_out(9) when gpio_dir(9) = '1' else 'Z';
shield_io(10) <= gpio_out(10) when gpio_dir(10) = '1' else 'Z';
shield_io(11) <= gpio_out(11) when gpio_dir(11) = '1' else 'Z';
shield_io(12) <= gpio_out(12) when gpio_dir(12) = '1' else 'Z';
shield_io(13) <= gpio_out(13) when gpio_dir(13) = '1' else 'Z';
shield_io(26) <= gpio_out(14) when gpio_dir(14) = '1' else 'Z';
shield_io(27) <= gpio_out(15) when gpio_dir(15) = '1' else 'Z';
shield_io(28) <= gpio_out(16) when gpio_dir(16) = '1' else 'Z';
shield_io(29) <= gpio_out(17) when gpio_dir(17) = '1' else 'Z';
shield_io(30) <= gpio_out(18) when gpio_dir(18) = '1' else 'Z';
shield_io(31) <= gpio_out(19) when gpio_dir(19) = '1' else 'Z';
shield_io(32) <= gpio_out(20) when gpio_dir(20) = '1' else 'Z';
shield_io(33) <= gpio_out(21) when gpio_dir(21) = '1' else 'Z';
shield_io(34) <= gpio_out(22) when gpio_dir(22) = '1' else 'Z';
shield_io(35) <= gpio_out(23) when gpio_dir(23) = '1' else 'Z';
shield_io(36) <= gpio_out(24) when gpio_dir(24) = '1' else 'Z';
shield_io(37) <= gpio_out(25) when gpio_dir(25) = '1' else 'Z';
shield_io(38) <= gpio_out(26) when gpio_dir(26) = '1' else 'Z';
shield_io(39) <= gpio_out(27) when gpio_dir(27) = '1' else 'Z';
shield_io(40) <= gpio_out(28) when gpio_dir(28) = '1' else 'Z';
shield_io(41) <= gpio_out(29) when gpio_dir(29) = '1' else 'Z';
shield_io(43) <= gpio_out(30) when gpio_dir(30) = '1' else 'Z';
shield_io(44) <= gpio_out(31) when gpio_dir(31) = '1' else 'Z';
end architecture behaviour;