Embedded/Microcontroller FPGA and Software Defined Radio

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I need a single chip solution for a control system and DSP
application.
The primary consideration is board area.  The second, cost.
Here's what I'm looking for:
  - 5V supply and I/O.
  - Embedded ADC (at least 1, preferably 8).  Slow rate (50 Hz).
  - Small FPGA fabric.  About the size of a small spartan.
  - Embedded block ram (4 KBytes).
  - Flash FPGA.  Would like not to have separate config prom.
  - Low I/O count.  I only need about 30 pins.

Does anything like this exist?  If 5V I/O is not possible, what's
needed to translate about 12 pins from 3.3/1.2 to 5V?

Also, what's envolved for FPGA based software defined radio?  I'd like
to build an RC (as in radio control airplane) receiver.  Most FM
radios hop between 2 frequencies to encode pulse widths which in turn
drive the RC servos.  So nothing digital.  It just needs to extract
the pulse train from the FM.  I would consider trading an FM receiver
chip for an external high-speed ADC and a larger FPGA if it buys
enough flexibility.

Regards,
Tom

Re: Embedded/Microcontroller FPGA and Software Defined Radio
snipped-for-privacy@launchbird.com (Tom Hawkins) wrote in message
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if you need true single chip solution it would only be possible
using full custom ASIC, this is out of the question.

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most semicon industry people say there is no 5V any more.
even 5V tolerant device are vanshing

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there is no FPGA with ADC (no real large FPGA at least)

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small like XC2S15?

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most FPGAs have that amount

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there is only 2 Flash (or instant on) FPGAs
1) lattice xPGA (only in large BGA pacakge)
2) Actel ProAsic+

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APA075, 100pin TQFP, 17EUR single qty, (price from mcs-ge.com)
 
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inputs series resistor
outputs direct connection
(in most cases)
 
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I hope Ray Andraka will reply on SDR side.

I have build model airplanes and I have build radio tranceivers and
transmitters. so the topic is kind interesting.

I guess you also need low power, right?

if you need low power then use TI MSP430 those are microcontrollers
that run out of wires plugged into an apple - no joke there was a demo
of webserver powered by an apple. Whatever you do with FPGA you need more
power.

you wanted single chip solution, this would be really hard!
www.cypressmicro.com advertises their products as Programmable SOC
well its RISC micro with configurable logic and analog blocks, but
the logic blocks are not PLD or FPGA unfortunatly.

you come to 3 chips so or so
1) radio front end
2) MCU or FPGA+config (or MCU holding FPGA config)

no way around it. very small micro could be run from internal memory
of ProAsic, then you could have, no still 3 chips, you need ADC


so use the radio chip
select some low power MCU (with ADC)
select some FPGA (possible loaded by the MCU)

antti

Re: Embedded/Microcontroller FPGA and Software Defined Radio
You don't ask for much, do you?  ;)

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The only hard part of your request is the single chip requirement.  You
can get a lot of peripherals and memory embedded into an MCU, either
small and cheap or some fairly large and powerful.  But not many (if
any) FPGAs have anything other than digital circuits.  One exception is
the PSOC from Cypress.  This is an MCU (don't remember the type, it is
either an 8051 derivative or a custom, 8 bit RISC chip) with
programmable peripheral blocks and memory.  The peripherals can be
digital like a UART or analog like an ADC.  If you only need 50 Hz and
not simultaneous, you can mux a single ADC.  The programmable digital
blocks may be enough for your needs if combined with MCU code.  

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I don't remember if the PSOC has 5 volt tolerant IOs.  These have
largely disappeared from newer families of logic.  There are several
ways to interface 3.3 volt IOs to 5 volt logic.  It partly depends on
the nature of your 5 volt interface.  If it is just TTL, then you likely
need to do nothing unless there is a chance the TTL levels will exceed
3.5 volts.  Or you can use a bus switch driven from about 4 volt Vcc as
a voltage limiter.  Or you can use a level shifter bus chip.  The bus
chips come in 8 and 16 bit widths and some are very small packages.  

If the PSOC does not float your boat, you will likely need a two chip
design, one for analog and one for FPGA.  You can get an MCU in either
chip along with the analog or FPGA.  There are Flash FPGAs such as the
Lattice XPLD devices.  You didn't give a price target, but I got a quote
once on the 512 macrocell part under $20, IIRC.  

Or if you get an MCU with analog IO, it will likely have enough Flash to
program one of the smaller FPGAs.  May be cheaper than the Flash FPGA.  

You didn't say anything about power.  Most FPGAs are pretty power
hungry.  The CPLDs can be *very* low power.  Both the Lattice parts and
the Xilinx Coolrunner parts can get way below 1 mA if not clocked at a
high rate.  


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It has been awhile since I have looked at digital radios, but if I am
still current, the term "software defined radio" implies the final
demodulation stage being done in software.  The processing required for
a digital radio means a high speed ADC at the IF stage and dedicated
hardware for conversion to baseband.  This can be done in an FPGA, but
you are looking at a lot of power to make it work.  This is likely way
overkill for your application.  You would still need the RF part of the
receiver.  Since an analog FM receiver is pretty much one chip, I don't
see how this would help you.  I expect you will find digital receivers
are an advantage when you can share the IF stage between a lot of
downconverters and demodulators such as in a cell phone base station or
similar application.  

--

Rick "rickman" Collins

snipped-for-privacy@XYarius.com
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Re: Embedded/Microcontroller FPGA and Software Defined Radio
Re: Embedded/Microcontroller FPGA and Software Defined Radio
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FPSLIC seemed like a dream when I first tried to use it, but
the tools are really bad (maybe they are a little better now)
Atmel claims the pricing starts from 7$ but only the 94K40 devices
are available (from digikey 45$) smaller devices digikey pricing
is $14 but non stock, and no idea where to get in small quantity

and the software licensing is really a killer, I spend 2 weeks
troubleshooting the license (involved phone calls to us support)
and then it times out all the time. So I dropped FPSLIC at least
temporarly from my desk.

A Spartan that can hold AVR core and same amount of logic as AT94K40
costs less than AT94K40, so why bother with FPSLIC?

antti

Re: Embedded/Microcontroller FPGA and Software Defined Radio
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Actually, neither Xilinx nor Atmel make a device that will fit all the
requirements since neither provide any mixed signal capability.  The
Xilinx parts also do not support 5 volt tolerance unless you use a
Coolrunner CPLD.  

The Cypress PSOC is the only device which provides all the required
functions, but I don't know if it is 5 volt tolerant or not.  

--

Rick "rickman" Collins

snipped-for-privacy@XYarius.com
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Re: Embedded/Microcontroller FPGA and Software Defined Radio
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PSoC does not have real configurable logic, it has digital and analog blocks
and some configuration, but you can not create any custom logic, only selected
from exisiting configurations. So there is no PLD on chip, only some reconfig
bits. PSoC was first marketed as having programmable logic onchip, but actually
it isnt there.

antti

Re: Embedded/Microcontroller FPGA and Software Defined Radio
How fast do you need to sample the ADCs, and how precise do they need to
be?  If simple enough, you could do a delta-sigma ADC with the FPGA,
although you still need an analog comparator.  You might be able to bias
an LVDS input to act as the comparator, although I have not tried it.  The
rest can be accomplished within an FPGA, although if power or cost are
considerations it may require more FPGA than you are willing to support.
I think a two chip solution, one being an FM receiver chip and the other a
microprocessor may be more appropriate.

Tom Hawkins wrote:

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--
--Ray Andraka, P.E.
President, the Andraka Consulting Group, Inc.
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