raddsp_axis_float_to_fixed Datasheet

Use Cases

AXI-Stream datapath integration where module boundaries need explicit ready/valid behavior.
Reusable FPGA DSP pipelines that need fixed-point, timing-aware implementation.
Memory-mapped control/status integration with software-visible register maps.

Block Diagram

VHDL Include And Instantiation Template

File Header

library ieee;
use ieee.std_logic_1164.all;
use ieee.numeric_std.all;

library radhdl;
-- Direct entity instantiation below does not require importing the entity name.
use radhdl.dsp.all;
-- Narrower alternative: use radhdl.dsp_transform.all;

Component Declaration

component raddsp_axis_float_to_fixed is
  generic (
    VENDOR : string := "xilinx";
    DEVICE_FAMILY : string := "generic";
    FIXED_WIDTH : positive := 16;
    FIXED_FRAC_BITS : natural := 15;
    CHANNEL_COUNT : positive := 1
  );
  port (
    m_axis_tvalid : out std_logic;
    m_axis_tready : in std_logic;
    m_axis_tdata : out std_logic_vector((CHANNEL_COUNT * FIXED_WIDTH) - 1 downto 0);
    m_axis_tlast : out std_logic;
    s_axis_tvalid : in std_logic;
    s_axis_tready : out std_logic;
    s_axis_tdata : in std_logic_vector((CHANNEL_COUNT * 32) - 1 downto 0);
    s_axis_tlast : in std_logic;
    clk : in std_logic;
    rst : in std_logic
  );
end component;

Direct Entity Instantiation

u_raddsp_axis_float_to_fixed : entity radhdl.raddsp_axis_float_to_fixed
  generic map (
    VENDOR          => "xilinx",
    DEVICE_FAMILY   => "generic",
    FIXED_WIDTH     => 16,
    FIXED_FRAC_BITS => 15,
    CHANNEL_COUNT   => 1
  )
  port map (
    m_axis_tvalid => <m_axis_tvalid_signal>,
    m_axis_tready => <m_axis_tready_signal>,
    m_axis_tdata  => <m_axis_tdata_signal>,
    m_axis_tlast  => <m_axis_tlast_signal>,
    s_axis_tvalid => <s_axis_tvalid_signal>,
    s_axis_tready => <s_axis_tready_signal>,
    s_axis_tdata  => <s_axis_tdata_signal>,
    s_axis_tlast  => <s_axis_tlast_signal>,
    clk           => <clk_signal>,
    rst           => <rst_signal>
  );

Generics

Name	Type	Default	Description
VENDOR	string	"xilinx"	Selects the vendor-specific implementation path, usually XILINX for DSP48/XPM-backed builds or generic for portable RTL.
DEVICE_FAMILY	string	"generic"	Identifies the target FPGA family so wrappers can choose the correct primitive or conservative portable behavior.
FIXED_WIDTH	positive	16	Sets the bit width for FIXED WIDTH values carried by this module.
FIXED_FRAC_BITS	natural	15	Sets the number of fractional bits used when scaling fixed-point arithmetic results.
CHANNEL_COUNT	positive	1	Sets the number of parallel sample lanes processed per handshake beat.

Ports

Name	Direction	Type	Description
m_axis_tvalid	out	std_logic	Output AXI-stream valid qualifier for the current result beat.
m_axis_tready	in	std_logic	Output AXI-stream ready input from the downstream block.
m_axis_tdata	out	std_logic_vector((CHANNEL_COUNT * FIXED_WIDTH) - 1 downto 0)	Output AXI-stream payload containing packed processed result lanes.
m_axis_tlast	out	std_logic	Output AXI-stream frame marker aligned with the processed result beat.
s_axis_tvalid	in	std_logic	Input AXI-stream valid qualifier for the current sample beat.
s_axis_tready	out	std_logic	Input AXI-stream ready response indicating this block can accept a beat.
s_axis_tdata	in	std_logic_vector((CHANNEL_COUNT * 32) - 1 downto 0)	Input AXI-stream payload containing packed sample or feature lanes.
s_axis_tlast	in	std_logic	Input AXI-stream frame marker for the final beat of a frame.
clk	in	std_logic	Clock for the associated synchronous logic and handshake domain.
rst	in	std_logic	Active-high synchronous reset for this clock domain.

Register Interfaces

No fixed register map was found; this section documents the exposed register/control interface ports.

Interface	Directions	Signals	Representative ports
M_AXIS	in, out	4	m_axis_tvalid, m_axis_tready, m_axis_tdata, m_axis_tlast
S_AXIS	in, out	4	s_axis_tvalid, s_axis_tready, s_axis_tdata, s_axis_tlast

Testbenches

tb_raddsp_axis_float_fixed captured waveform

Source: dsp/hdl/testbenches/tb_raddsp_axis_float_fixed.vhd

Self-checking or stimulus-focused testbench for axis float fixed. Exercises representative handshakes, reset behavior, frame boundaries, and numeric corner cases for regression runs.

Artifacts: status, vcd

Data Plots

Float to Q8.8 Fixed Conversion

Directed IEEE-754 input values converted into signed Q8.8 fixed-point output codes.

Q8.8 Fixed to Float Conversion

Directed signed Q8.8 input codes converted back into real-valued float equivalents.

Captured GHDL Waveform

Source: dsp/hdl/testbenches/tb_raddsp_axis_float_fixed.vhd

Horizontal Vertical

clk

rst

f2x_s_valid

f2x_s_ready

f2x_s_data[31:0]

f2x_s_last

f2x_m_valid

f2x_m_data[15:0]

f2x_m_last

x2f_s_valid

x2f_s_ready

x2f_s_data[15:0]

x2f_s_last

x2f_m_valid

x2f_m_data[31:0]

x2f_m_last

out_valid_r

out_data_r[15:0]

out_last_r

ready_i

out_data_r[31:0]

S_AXIS

M_AXIS

M_AXIS interface signals

M_AXIS Interface Waveform

Source: dsp/hdl/testbenches/tb_raddsp_axis_float_fixed.vhd

Horizontal Vertical

m_axis_tvalid

m_axis_tready

m_axis_tdata[15:0]

m_axis_tlast

m_axis_tdata[31:0]

S_AXIS interface signals

S_AXIS Interface Waveform

Source: dsp/hdl/testbenches/tb_raddsp_axis_float_fixed.vhd

Horizontal Vertical

s_axis_tvalid

s_axis_tready

s_axis_tdata[31:0]

s_axis_tlast

s_axis_tdata[15:0]

Sources

dsp/hdl/raddsp/src/raddsp_axis_float_to_fixed.vhd