When the Steckschwein project team implemented banking logic for 512k RAM using a Xilinx XC9572 CPLD, they knew they were working with deprecated hardware. What they couldn't anticipate was AMD/Xilinx's decision to terminate its entire Complex Programmable Logic Device (CPLD) line in 2024—a move that has stranded countless embedded systems and retrocomputing projects reliant on these chips.

"The upgrade path would be the successor family XC95..XL. Those have been rather expensive lately, and finally AMD/Xilinx axed their whole CPLD line in 2024, leaving us at a dead end," states the Steckschwein team.

This predicament highlights a critical industry challenge: CPLDs once served as the workhorses for 'glue logic'—managing memory banking, I/O interfacing, and simple state machines. But with major players like Xilinx exiting the market and remaining manufacturers scaling back, engineers face limited options:

The Shrinking CPLD Ecosystem

  • Market Contraction: Only Lattice Semiconductor and Microchip still actively produce CPLDs, focusing on niche industrial applications rather than broad availability.
  • Cost Surge: Remaining XC95XL chips now command premium prices due to scarcity, making them impractical for hobbyist or low-volume projects.
  • No Direct Successors: Modern FPGAs often require more power, complex toolchains, and external configuration memory—overkill for simple logic tasks.

Survival Strategies for Hardware Developers

  1. FPGA Migration: Low-power FPGAs like Lattice's iCE40 or CrossLink-NX offer alternatives but require rewriting VHDL/Verilog logic and redesigning power systems.
  2. Microcontroller Substitution: Modern MCUs with programmable logic (e.g., Raspberry Pi RP2040's PIO) can handle some glue logic tasks but lack deterministic timing.
  3. Open-Source Alternatives: Projects like nMigen enable FOSS toolchain development, reducing dependency on proprietary ecosystems.
  4. Last-Time Buys: Stockpiling remaining CPLD inventory risks future maintenance nightmares when stocks deplete.

This crisis underscores a harsh reality: hardware longevity is evaporating. As semiconductor giants prioritize high-margin products, embedded developers must prioritize forward-compatible design—modularizing critical logic, documenting interfaces rigorously, and embracing community-driven solutions. The Steckschwein team's struggle is a microcosm of an industry-wide reckoning: when foundational components vanish, innovation must fill the void or risk becoming obsolete alongside the hardware it depends on.

Source: Steckschwein Project