The C139A core implements a link layer controller for the high-speed, high-bandwidth serial bus known commercially as FireWireTM and i.LinkTM. The core conforms to the IEEE 1394-1995 and 1394a-2000 specifications. It is similar to the popular Texas Instruments TSB12LV32 General Purpose Link Layer Controller, but includes a 32-bit APB interface for easy connection with an AMBATM bus host system. (AHB and other standard interfaces are also available.) The C1394A can interface with any 1394-compliant physical layer (PHY) device, and includes easy-to-apply C-language software functions for all basic operations (options provide serial bus management and the transaction layer). It is FPGA-proven and has been exercised in a FireWire video camera demonstration system. ASIC results show it to require less than 39,000 gates. The C1394A is a testable, microcode-free design developed for reuse in ASICs and FPGAs. It is fully synchronous and has no internal three-state buses. A complete verification environment helps designers verify the functioning and compliance of the core, and additional aids for system-on-chip simulation are available.