Embedded/Microcontroller FPGA and Software Defined Radio

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

Reply to
Tom Hawkins
Loading thread data ...

if you need true single chip solution it would only be possible using full custom ASIC, this is out of the question.

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

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

small like XC2S15?

most FPGAs have that amount

there is only 2 Flash (or instant on) FPGAs

1) lattice xPGA (only in large BGA pacakge) 2) Actel ProAsic+

APA075, 100pin TQFP, 17EUR single qty, (price from mcs-ge.com)

inputs series resistor outputs direct connection (in most cases)

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!

formatting link
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

Reply to
Antti Lukats

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.

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.

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

rick.collins@XYarius.com
 Click to see the full signature
Reply to
rickman

looked at the atmel fpslic devices? big cost is the license after the one in the dev kit runs out(4 months).

basically an avr + small fpga

formatting link
formatting link
formatting link
formatting link

Reply to
Alex Gibson

[***]

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

Reply to
Antti Lukats

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

rick.collins@XYarius.com
 Click to see the full signature
Reply to
rickman

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

Reply to
Antti Lukats

--

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

401/884-7930 Fax 401/884-7950 email snipped-for-privacy@andraka.com
formatting link

"They that give up essential liberty to obtain a little temporary safety deserve neither liberty nor safety." -Benjamin Franklin, 1759

Reply to
Ray Andraka

ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.