.
Andrew Warren wrote:
>     It doesn't appear hard to design a PIC-compatible core in VHDL
>     or Verilog (see http://www.opencores.org/projects/minirisc/ for
>     an example), so if someone wanted a PIC in his CPLD or FPGA, he'd
>     probably just spend a couple days and design it himself.  Except
>     for (maybe) some legal concerns, there's no real reason to wait
>     for Microchip to release an "official" core.
>=20

   You are right:
Quotations from http://xilinx.com/xapp/xapp213.pdf:

----------------------------------------------------------------------
Summary
   The Constant (k) Coded Programmable State Machine=20
(PicoBlaze) solution presented in this application note is=20
a fully embedded 8-bit microcontroller macro for the VirtexT=20
and SpartanR-II devices. The module is remarkably small=20
at just 35 CLBs, less than half of the smallest Spartan=20
XC2S15 device, and virtually free in an XCV2000 device=20
by consuming less than 0.37% of the device CLBs.
   This PicoBlaze solution provides 49 different instructions,=20
16 registers, 256 directly and indirectly addressable ports,=20
and a maskable interrupt at 35 million instructions per second
(MIPs). This performance exceeds that of traditional discrete=20
microcontroller devices, making the PicoBlaze a cost-attractive=20
solution for data processing as well as control algorithms.
   Fully embedded including the program memory, the PicoBlaze=20
solution can be connected to many other functions and=20
peripherals tuned to a specific design. Processing distributed=20
over multiple PicoBlaze processors within a single device is=20
suitable for applications such as neural networks.

Conclusion=20
   A microprocessor module does not have to be large or=20
expensive when implemented in a Virtex or Spartan-II device.=20
The Virtex architectural features (block memory, distributed=20
memory, dedicated multiplexers, and carry logic) are ideal=20
for the construction of fully embedded microprocessor modules.
   The PicoBlaze macro is a simple 8-bit processor with an=20
instruction set for basic control functions and data manipulation.=20
This is achieved with just 35 CLBs and one block RAM. Even
with a silicon utilization over performance objective, over=20
30 MIPs of processing power shows the very high performance=20
provided by Xilinx devices. This simple 8-bit processor achieves
 significant data processing algorithms and control. For example,=20
performance measurements of 150,000 16-bit multiplications=20
per second are available for audio and control digital signal
processing.
   When a processor is completely embedded within an FPGA,=20
no I/O resources are required to communicate with other modules=20
in the same FPGA. Additionally, system design flexibility is=20
included along with savings on PCB requirements, power=20
consumption, and EMI. Whenever a special type of instruction is=20
required, it can be created in hardware (other CLBs) and=20
connected to the PicoBlaze solution as a kind of coprocessor.=20
Indeed, there is nothing to prevent a coprocessor from being=20
another PicoBlaze module. In this way, even the 256-instruction
program length is not a limitation.
   Finally, the optimal processor results when the instruction=20
set is tuned to the system algorithms. By creating individual=20
processor architectures with flexible software inside the hardware,=20
the PicoBlaze solution shows how programmable state machines=20
are very silicon efficient.
------------------------------------------------------------------------
------------

   Mike.

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