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library neorv32;
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library neorv32;
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use neorv32.neorv32_package.all;
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use neorv32.neorv32_package.all;
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entity neorv32_cfs is
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entity neorv32_cfs is
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generic (
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generic (
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CFS_CONFIG : std_ulogic_vector(31 downto 0) := x"00000000" -- custom CFS configuration conduit generic
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CFS_CONFIG : std_ulogic_vector(31 downto 0); -- custom CFS configuration generic
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CFS_IN_SIZE : positive := 32; -- size of CFS input conduit in bits
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CFS_OUT_SIZE : positive := 32 -- size of CFS output conduit in bits
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);
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);
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port (
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port (
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-- host access --
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-- host access --
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clk_i : in std_ulogic; -- global clock line
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clk_i : in std_ulogic; -- global clock line
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rstn_i : in std_ulogic; -- global reset line, low-active, use as async
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rstn_i : in std_ulogic; -- global reset line, low-active, use as async
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sleep_i : in std_ulogic; -- set if cpu is in sleep mode
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sleep_i : in std_ulogic; -- set if cpu is in sleep mode
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-- interrupt --
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-- interrupt --
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irq_o : out std_ulogic; -- interrupt request
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irq_o : out std_ulogic; -- interrupt request
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irq_ack_i : in std_ulogic; -- interrupt acknowledge
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irq_ack_i : in std_ulogic; -- interrupt acknowledge
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-- custom io (conduits) --
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-- custom io (conduits) --
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cfs_in_i : in std_ulogic_vector(31 downto 0); -- custom inputs
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cfs_in_i : in std_ulogic_vector(CFS_IN_SIZE-1 downto 0); -- custom inputs
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cfs_out_o : out std_ulogic_vector(31 downto 0) -- custom outputs
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cfs_out_o : out std_ulogic_vector(CFS_OUT_SIZE-1 downto 0) -- custom outputs
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);
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);
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end neorv32_cfs;
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end neorv32_cfs;
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architecture neorv32_cfs_rtl of neorv32_cfs is
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architecture neorv32_cfs_rtl of neorv32_cfs is
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addr <= cfs_base_c(31 downto lo_abb_c) & addr_i(lo_abb_c-1 downto 2) & "00"; -- word aligned
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addr <= cfs_base_c(31 downto lo_abb_c) & addr_i(lo_abb_c-1 downto 2) & "00"; -- word aligned
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wren <= acc_en and wren_i; -- full 32-bit word write enable
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wren <= acc_en and wren_i; -- full 32-bit word write enable
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rden <= acc_en and rden_i; -- the read access is always a full 32-bit word wide; if required, the byte/half-word select/masking is done in the CPU
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rden <= acc_en and rden_i; -- the read access is always a full 32-bit word wide; if required, the byte/half-word select/masking is done in the CPU
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-- CFS Generic ----------------------------------------------------------------------------
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-- CFS Generics ---------------------------------------------------------------------------
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-- -------------------------------------------------------------------------------------------
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-- -------------------------------------------------------------------------------------------
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-- In its default version, the CFS provides a single generic: CFS_CONFIG. This generic can be set using the processor top's IO_CFS_CONFIG generic.
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-- In its default version, the CFS provides the configuration generics. single generic:
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-- It is intended as a "conduit" to propagate custom implementation option from the top down to this entiy.
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-- CFS_IN_SIZE configures the size (in bits) of the CFS input conduit cfs_in_i
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-- CFS_OUT_SIZE configures the size (in bits) of the CFS output conduit cfs_out_o
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-- CFS_CONFIG is a blank 32-bit generic. It is intended as a "generic conduit" to propagate custom configuration flags from the top entity down to this entiy.
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-- CFS IOs --------------------------------------------------------------------------------
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-- CFS IOs --------------------------------------------------------------------------------
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-- -------------------------------------------------------------------------------------------
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-- -------------------------------------------------------------------------------------------
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-- By default, the CFS provides two IO signals (cfs_in_i and cfs_out_o) that are available at the processor top entity.
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-- By default, the CFS provides two IO signals (cfs_in_i and cfs_out_o) that are available at the processor top entity.
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-- ack_o <= rden; -- use this construct if your CFS is read-only
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-- ack_o <= rden; -- use this construct if your CFS is read-only
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-- ack_o <= wren; -- use this construct if your CFS is write-only
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-- ack_o <= wren; -- use this construct if your CFS is write-only
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-- ack_o <= ... -- or define the ACK by yourself (example: some registers are read-only, some others can only be written, ...)
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-- ack_o <= ... -- or define the ACK by yourself (example: some registers are read-only, some others can only be written, ...)
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-- write access --
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-- write access --
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for i in 0 to 3 loop -- iterate over all 4 bytes in a word
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for i in 0 to 3 loop
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if (wren = '1') then -- word-wide write-access only!
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if (wren = '1') then -- word-wide write-access only!
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case addr is -- make sure to use the internal 'addr' signal for the read/write interface
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case addr is -- make sure to use the internal 'addr' signal for the read/write interface
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when cfs_reg0_addr_c => cfs_reg_wr(0) <= data_i; -- for example: control register
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when cfs_reg0_addr_c => cfs_reg_wr(0) <= data_i; -- for example: control register
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when cfs_reg1_addr_c => cfs_reg_wr(1) <= data_i; -- for example: data in/out fifo
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when cfs_reg1_addr_c => cfs_reg_wr(1) <= data_i; -- for example: data in/out fifo
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when cfs_reg2_addr_c => cfs_reg_wr(2) <= data_i; -- for example: command fifo
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when cfs_reg2_addr_c => cfs_reg_wr(2) <= data_i; -- for example: command fifo
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