General Technical Discussion

[dzunior]

Hi all,

I´m wondering whether MCU+FPGA is still something that people are looking for or there´s no need for this kind of designs/boards? I´m thinking of low budget FPGAs (not BGA big ones) and some Cortex like MPUs.
I´ve heard about some projects this type some time ago but still haven´t seen anything special. Maybe if there were some tools which would make it easier to use (as it is with Arduino) people would give it a try?

Thanks,
Dominik

[mcgett]

Oh, you mean like the Zynq-7000 family?

http://www.xilinx.com/products/silicon-devices/epp/zynq-7000/index.htm

[eilert]

Hi,

what's the price gap between the smallest Zync device and some ARM-Arduino+S6 FPGA addon?

I think that's the sort of thing that Dominik had in mind.

This:

http://eda360insider.wordpress.com/2012/06/05/itching-to-try-out-the-xilinx-zync-7000-epp-ask-your-d...

would probably be to expensive for the average hobbyist even if the academic price is taken into account.

But the reason that this combination is rarely found in the low cost sector may have some explanation.

If a designer is familiar with FPGAs anyway, why should he add an external MCU?

Even small S6 devices are capable of implementing a Microblaze design, and all the logic for combining CPU and other stuff can be done inside one design.

Also for the one who can not afford the EDK, there's now the Microblaze MCS core which offers enough computing power for most small projects.

S6 Boards are widely available, but most of them are huge compared to the Arduino form factor. (OR if they are small, they are either costly or very specialized)

One could think of a S6-Arduino with some nicely predefined EDK-Design that ccould be expanded with additional logic designs by the user. Then adapting the Arduino-IDE to this MB-core design should be possible too.

It could be questioned if the average Arduino user will ever be able to use the powerful features of the FPGA and also wether the limited number of standard Arduino IOs makes sense with a FPGA on the PCB. Others might love it, who knows.

Kind regards

  Eilert

[dzunior]

Hi Eilert,

Yes, I was thinking more of small ARM + FPGA. The thing with Microblaze MCS (thanks for mentioning it,I didn't know it's available as a standalone) is that it takes some resources - internal memory specially  (if you use them in any TQFP FPGA - hobbyst favorite package), and we still need some external ICs to have a serial/USB communication, ADC,DAC (which is now included in almost any IC). Also debugging of MB without having a Xilinx cable is a bit painful (and afaik it's still quite expensive tool compared to diy debuggers for uCs). So I was thinking to leave FPGA for things it fits the best - high speed, parallel tasks, lot of GPIOs and use the external uC for communication,configuration etc.

Best regards,

Dominik

[bassman59 · Accepted solution]

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dzunior wrote:

Hi Eilert,

Yes, I was thinking more of small ARM + FPGA. The thing with Microblaze MCS (thanks for mentioning it,I didn't know it's available as a standalone) is that it takes some resources - internal memory specially  (if you use them in any TQFP FPGA - hobbyst favorite package), and we still need some external ICs to have a serial/USB communication, ADC,DAC (which is now included in almost any IC). Also debugging of MB without having a Xilinx cable is a bit painful (and afaik it's still quite expensive tool compared to diy debuggers for uCs). So I was thinking to leave FPGA for things it fits the best - high speed, parallel tasks, lot of GPIOs and use the external uC for communication,configuration etc.

Best regards,

Dominik

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Do yourself a favor and do as you suggest: use a standalone micro of your choice and marry it to the FPGA using whatever interface you like (EMIF a-la SiLabs 8051, SPI, I2C, whatever). The micro will be cheaper and the FPGA will be much cheaper. The micro tools are likely to be much more mature and debugging will be greatly simplified. And in many cases, the system performance will be better, too.