Asymmetric multicore on-chip can be a challenge because of the lead time required to develop a custom chip. Falling FPGA prices and rising FPGA functionality offer an alternative for evaluation as well as production. This is especially true as soft-core processors like Xilinxâ??s MicroBlaze v7 move higher in the food chain.
This latest edition of MicroBlaze incorporates a number of new features, including a memory management unit (MMU), enabling it to run higher-end, protected operating systems like Linux. A single-core MicroBlaze requires only a fraction of even a low-end Spartan-3E FPGA like the one available on Xilinxâ??s EDK, which uses about 1100 lookup tables (LUTs) (see the figure). There are fewer in the Virtex-5 FPGA, which uses a more advanced six-input LUT.
Thanks to a multiport memory controller, multiple cores can be implemented. It also offers hardware-based mutex mailbox functionality. A new gigabit Ethernet MAC with a Treck Inc. Ethernet stack boosts performance by a factor of five compared to the prior version of MicroBlaze, MAC, and opensource stack.
Additional cores might be MicroBlaze units with custom instructions or enhancements. They also could be completely different cores, permitting an asymmetric mix with a system that still supports standard, high-end operating systems.