XAP processor

The XAP processor is a RISC processor architecture developed by Cambridge Consultants since 1994. XAP processors are a family of 16-bit and 32-bit cores, all of which are intended for use in an application-specific integrated circuit or ASIC chip design. XAP processors were designed for use in mixed-signal integrated circuits for sensor or wireless applications including Bluetooth, ZigBee, GPS, RFID or Near Field Communication chips. Typically these integrated circuits are used in low cost, high volume products that are battery-powered and must have low energy consumption. There are other applications where XAP processors have been used to good effect, such as wireless sensor networks and medical devices, e.g. hearing aids.

The XAP soft microprocessor has been implemented in several on-chip design styles, including self-timed asynchronous circuit, 1-of-4 encoding, fully synchronous circuit, and FPGA. This makes it useful for making fair comparisons between on-chip design styles.

The first XAP processor was XAP1, designed in 1994 and used for a number of wireless and sensor ASIC projects at Cambridge Consultants. It was a very small, 3,000-gate, Harvard architecture, 16-bit processor with a 16-bit data bus and an 18-bit instruction bus intended for running programs stored in on-chip read-only memory or ROM. Data and instructions were each addressed by separate 16-bit address bus.

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