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Some ZPU users and why they chose the ZPU

The ZPU was developed as a small portable soft CPU while not backing down on the requirement of having a standard GCC toolchain, when this is combined with a FreeBSD license it makes for a very attractive alternative.

With small and simple as a design goal, the ZPU is not a high performance CPU. However, it punches above it's weight when running on top of a slow memory subsystem due to it's very tight code size. ZPU code size is ~80% of that of ARM Thumb. On the other hand, when the ZPU runs at 50 MHz and higher it has ample of performance for simple applications.

The ZPU can be used with no operating system, but it also has an eCos RTOS HAL support(open source and royalty free of course).

National Semiconductor

National Semiconductor offers an eval kit to demonstrate usage of high speed SDI parts. When they put together the SDALTEVK development kit, they looked for a vendor neutral CPU in their FPGA IP. ZPU with it's FreeBSD license and GCC toolchain fit the bill perfectly.

In this application the ZPU implements support for a simple terminal interface, handling of push buttons and control of registers.

Links: App note 1971

Ross Video

Ross Video looked for a soft CPU that could perform closed captioning processing in an OpenGear product. The ZPU was a good choice as it was able to meet a 100MHz clocking requirement in a low end FPGA, and had ample processing power for the job. The FreeBSD license provided portability of the ZPU core so that the entire design could be targeted to any FPGA family. Also, the GCC compiler allows the same software written for the ZPU to work on other processors with a simple re-compile.

Other uses

The ZPU is also used in academia, where the simple architecture is a boon for students who need to quickly get up to speed when learning about various aspects of CPUs, FPGA tools, etc.

Tecnische universit├Ąt dortmund

The ZPU is being used as a basis for the configurable computing project LavA, which involves the study of a massively parallel system to analyze multicore FPGA energy use and novel operating concepts.

The current implementation on a Virtex 5 (XUPV5-LX110T) packs up to 98 ZPUs plus IPC controllers and interconnect onto the FPGA.

We want to hear your story!

If you use the ZPU professionally, we would love to hear from you. Please send an email to or post a message to the zylin-zpu mailing list.

ZPU license

As of Jan 1. 2008, Zylin had the complete Copyright for the ZPU: RTL, documentation, GCC toolchain, simulators, etc. Other copyright holders have contributed since.

The simple story is that Zylin chose to use a FreeBSD license for the RTL and a GPL license for the rest. This essentially means that you can use the RTL in proprietary code or open source code and that it will be compatible with any license out there.

Formal quote

Contact us for a formal quote on your turnkey ZPU solution.