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-- #################################################################################################
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-- #################################################################################################
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-- # << NEORV32 - Custom Functions Subsystem (CFS) >> #
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-- # << NEORV32 - Custom Functions Subsystem (CFS) >> #
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-- # ********************************************************************************************* #
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-- # ********************************************************************************************* #
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-- # For tightly-coupled custom co-processors. Provides 32x32-bit memory-mapped registers. This is #
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-- # For tightly-coupled custom co-processors. Provides 32x32-bit memory-mapped registers. #
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-- # just an "example/illustration template". Modify this file to implement your own custom design #
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-- # This is just an "example/illustration template". Modify this file to implement your own #
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-- # logic. #
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-- # custom design logic. #
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-- # ********************************************************************************************* #
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-- # ********************************************************************************************* #
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-- # BSD 3-Clause License #
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-- # BSD 3-Clause License #
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-- # #
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-- # #
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-- # Copyright (c) 2021, Stephan Nolting. All rights reserved. #
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-- # Copyright (c) 2021, Stephan Nolting. All rights reserved. #
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-- # #
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-- # #
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data_o : out std_ulogic_vector(31 downto 0); -- data out
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data_o : out std_ulogic_vector(31 downto 0); -- data out
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ack_o : out std_ulogic; -- transfer acknowledge
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ack_o : out std_ulogic; -- transfer acknowledge
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-- clock generator --
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-- clock generator --
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clkgen_en_o : out std_ulogic; -- enable clock generator
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clkgen_en_o : out std_ulogic; -- enable clock generator
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clkgen_i : in std_ulogic_vector(07 downto 0); -- "clock" inputs
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clkgen_i : in std_ulogic_vector(07 downto 0); -- "clock" inputs
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-- CPU state --
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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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-- custom io (conduits) --
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-- custom io (conduits) --
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cfs_in_i : in std_ulogic_vector(CFS_IN_SIZE-1 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(CFS_OUT_SIZE-1 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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-- Make sure to deactivate the CFS's clkgen_en_o if no clocks are required in here to reduce dynamic power consumption.
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-- Make sure to deactivate the CFS's clkgen_en_o if no clocks are required in here to reduce dynamic power consumption.
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clkgen_en_o <= '0'; -- not used for this minimal example
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clkgen_en_o <= '0'; -- not used for this minimal example
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-- Further Power Optimization -------------------------------------------------------------
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-- -------------------------------------------------------------------------------------------
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-- The CFS can decide to go into low-power mode (by disabling all switching activity) when the CPU enters sleep mode.
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-- The sleep_i signal is high when the CPU is in sleep mode. Any interrupt including the CFS's irq_o interrupt request signal
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-- will wake up the CPU again.
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-- sleep_i
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-- Interrupt ------------------------------------------------------------------------------
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-- Interrupt ------------------------------------------------------------------------------
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-- -------------------------------------------------------------------------------------------
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-- -------------------------------------------------------------------------------------------
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-- The CFS features a single interrupt signal. This interrupt is connected to the CPU's "fast interrupt" channel 1.
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-- The CFS features a single interrupt signal, which is connected to the CPU's "fast interrupt" channel 1.
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-- The interrupt is single-shot. Setting the irq_o signal high for one cycle will generate an interrupt request.
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-- The interrupt is high-level-active. When set, the interrupt appears as "pending" in the CPU's mie register
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-- It is recommended to implement some CFS mechanisms (like a register that needs to be written) in order to allow
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-- ready to trigger execution of the according interrupt handler.
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-- another generation on an interrupt request (simple acknowledgement).
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-- Once set, the irq_o signal **has to stay set** until explicitly acknowledged by the CPU
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-- (for example by reading/writing from/to a specific CFS interface register address).
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irq_o <= '0'; -- not used for this minimal example
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irq_o <= '0'; -- not used for this minimal example
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-- Read/Write Access ----------------------------------------------------------------------
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-- Read/Write Access ----------------------------------------------------------------------
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