1-GHz Cortex-A8 maintains cycle-accurate operation
By Robert Cravotta, Technical Editor -- EDN, July 31, 2009
Samsung Electronics and Intrinsity have worked together to produce an ARM Cortex-A8 processor, Hummingbird, that can operate at 1 GHz in a 45-nm, low-power process and maintain the same cycle-accurate and Boolean-equivalent operation as the original Cortex-A8 RTL (register-transfer-level) specification. The companies attained this clock rate by applying custom-designed circuit/memory structures and Intrinsity’s enhanced RTL FastCore and Fast14 high-speed domino logic to timing-critical paths in the Cortex-A8 RTL core. The latest generation of Intrinsity’s NDL (one-of-N-domino-logic) implementation now supports seamless mixing between domino logic and static logic in a standard-cell-synthesized design. This feature enables the core to use only those NDL gates that are 25 to 50% faster than static-logic gates, in those critical-path circuits in which they impact the overall clock rate. This mixing enables the system to consume less static and dynamic than earlier implementations of other cores that used the NDL gates throughout the entire core.
Samsung is implementing SOC (system-on-chip) devices using the Hummingbird core. The core includes 32-kbyte instruction and data caches, 512 kbytes of L2 memory, and an ARM Neon multimedia extension. The companies have not released any power figures. To minimize power consumption, the core supports multiple drain-to-drain-voltage and frequency operation that includes a minimum supply voltage of 1V so that the core can target mobile devices.
Intrinsity aims its Fast14 technology at companies that are pushing processor cores at the upper end of the technology that synthesizable cores target. Maintaining cycle-accurate and Boolean-equivalent operation means that the implementation team can use all of the test and verification code for the processor’s RTL specification without modification. The Fast14 technology is available now.
