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.