New core enables hardware conversion of mono or stereo PDM streams to PCM, 
with configurable audio processing and flexible SoC interfaces. 


Woodcliff Lake, NJ — March 24, 2026 — CAST, a leading provider of semiconductor
intellectual property cores, today announced a core that gives ASIC and FPGA designers a
practical way to add direct digital microphone input to their SoCs and subsystems.  

The new PDM2PCM PDM Receiver/ PDM-to-PCM Converter IP core converts mono or stereo Pulse Density  Modulation (PDM) streams into standard Pulse Code Modulation (PCM) audio. Quite flexible, it provides programmable output widths from 2 to 32 bits and       supports standard audio
sampling rates via an adjustable oversampling ratio from 32x to 256x.

Designed to reduce software overhead and simplify implementation, the PDM2PCM core
performs the key audio-processing steps in hardware to convert incoming PDM data into
usable PCM audio. Its processing pipeline performs many functions that would otherwise
require considerable expertise to design, including decimation and filtering; configurable DC
offset and low-frequency noise removal; digital volume control; soft mute; dithering;
saturation protection; and maximum-amplitude tracking for run-time clipping and headroom
monitoring.  


       “Many system developers want the benefits of digital microphones without having to
       spend design effort and valuable processing resources on the conversion path,” said Evan
       Price, audio interfaces product manager at CAST. “This new PDM2PCM core gives them a
       compact, integration-ready hardware solution that captures PDM audio, whether mono or
       stereo, converts it to clean PCM data, and delivers it into the SoC using the interface style
       that best fits their architecture.” 


Flexible Integration for ASIC and FPGA Designs 

Sourced from IObundle, the PDM2PCM core is built for straightforward use in modern SoC
architectures. Its control and status registers can be accessed through either AMBA® AXI-Lite
or APB, while PCM output data can be delivered through an AXI4-Stream interface for
continuous sample flow or through an AXI4 manager interface for burst transfers directly to
external memory. Additionally, the core supports an AXI4 slave interface with DMA handshake
signals (dma_req and dma_ack), enabling direct DMA transfers triggered by FIFO threshold
interrupts. 


The core operates across separate system-clock and PDM-bit-clock domains, helping designers
integrate audio capture cleanly into broader digital subsystems. The core is delivered as
synthesizable Verilog RTL or as a targeted FPGA netlist, together with an integration testbench,
synthesis scripts, timing constraints, comprehensive documentation, a bare-metal C driver, and
example firmware. 


High-Fidelity Audio Path with Compact Implementation 

The PDM2PCM core is suited to a wide range of embedded designs that need direct digital audio
capture, including voice-enabled devices, industrial and consumer systems, and other products
built around ASICs or FPGAs. Representative implementation results on the product page show
a compact footprint, including a stereo ASIC implementation requiring 39K gates and no RAM in
TSMC 28nm at a 500 MHz system clock, plus FPGA characterizations on AMD Kintex™
UltraScale™ and Altera Cyclone® V devices.  


Available Now 

The introduction of the PDM2PCM core expands our audio-interface offerings with a practical
hardware bridge between digital microphone inputs and standard PCM audio data used
elsewhere in the system. The core is available now for ASIC and FPGA designs. For technical
details, evaluation options, or pricing, visit the PDM2PCM product page or contact CAST.  


About CAST 

Computer Aided Software Technologies, Inc. (CAST) is a silicon IP provider founded in 1993.
The company's ASIC and FPGA IP product line includes microcontrollers and processors;
compression engines for data, images, and video; interfaces for automotive, aerospace, and
other applications; networking stacks and offloading engines; various common peripheral
devices; and security primitives and comprehensive SoC security modules. 


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CAST is a trademark of Computer Aided Software Technologies Inc. 
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