Hello,
I struggle to find a hand solderable (soic ? msop ?) DSP programmable chip
I tried a teensy and a raspberry pi to DSP some simple audio to make audio effects based on FFT/iFFT
back in the day there were dedicated chips and (embeded & small) boards, but it's so hard to find nowadays
thanks for the time you'll spend on this one
Phil
The way that problem is solved these days is by getting an evaluation board. Most chip companies have them for the parts they have in current production.
DigiKey coughs up 53 boards that have DSPs from my favorite brands (plus Microchip).
What about DSPic from Microchip?
There are several versions easy to solder.
You can eve find some DIP Cus
I cant really find any info about this
more like general farnel dev boards and stuffs
any chip in particular ? tutorials ? recommendations ?
thanks
It is interesting how things changed in the DSP industry. Nowadays most DSP features exists in MCUs as engines and software libraries.
Have a look at the ARM-based board STM nucleo board. It has the DSP capabilities and a large user base and support.
https://www.st.com/en/evaluation-tools/stm32-nucleo-boards.html
You can check the board price on digikey or sparkfun. However this board in particular is very cheap, it’s around $15.
https://www.digikey.com/product-detail/en/stmicroelectronics/NUCLEO-F446RE/497-15882-ND/5347712
Maybe it looks big in the pictures but it’s almost the same size as the RP. If you’re for a smaller size google the stm32 blue pill but make sure it has the floating point processor unit (FPU).
rp zero is 2.5cm wide
teensy, is like 1.5cm wide
Nucleo32 is a hair under 1.9cm. The L4s are nice little chips. Never tried to do spectral processing with them, but gut feel is it would be doable.
or this dude is pretty new but looks mean for the size: https://www.digikey.com/products/en?WT.z_cid=sp_497_0928_buynow&Enterprise=44〈=en&Vendor=497&mpart=NUCLEO-G431KB
Phil-
At first I was going to suggest you use an older DSP, but it would have to much older, 15 years, maybe closer to 20.
Another idea is to choose a small, modern DSP you like, then look for an SMD to pin adapter, you can search for "SMD adapters". There are lots of providers, normally these are used for test/debug purposes. It might not look good, but could be quite functional, especially if you avoid using a DSP that requires external DRAMs and other high speed connections.
-Jeff
Phil-
Hmm, in that case maybe look at TI's fixed-point C5416 or C5510. These came out in 2000-2006 time-frame, but TI still shows them as "Active". Note the 5416 has a LQFP-144 package -- not exactly easy to solder, but do-able.
Both are very small. This page has some pics showing just how small:
https://signalogic.com/sigc54x
What size FFTs do you need to do ?
-Jeff
it depends, 64 to 4096, but are there no more recent chips ?
Phil-
Maybe have a look at the ADI "SigmaDSP" line:
https://www.analog.com/en/about-adi/news-room/press-releases/2017/5-23-2017-analog-devices-next-generation-dsp-for-automotive-audio-applications.html
These were released in 2017. They come in an LFCSP package, which believe it or not looks hand solderable (if you're skillful).
-Jeff
thanks I'll check this out, mate
Phil-
Even better, how to connect SigmaDSP devices to Raspberry Pi via I2S:
https://ez.analog.com/dsp/sigmadsp/f/q-a/65427/con...
You can't miss, hehe.
-Jeff
sheers mate, I'll definetely have a look at this
The FV-1 from Spin Semiconductor might work for you. It's used in many guitar effects pedals, amps and mixers. It's particularly well-suited to reverb and delay effects. It's a 28 pin SOIC and even I can solder it (I'm 68 next week and only have one good eye and a n illuminated magnifier!).
In the US it's distributed by Experimental Noize and in Europe its available from Profusion in the UK.
http://www.experimentalnoize.com/manuals/FV-1.pdf
also checked the application notes, it does not talk about any FFT/iFFT :-(
The instruction set link is further down the page. http://www.spinsemi.com/Products/datasheets/spn1001-dev/SPINAsmUserManual.pdf
Sorry, I missed your original reference to FFT/iFFT. AFAIK There are no specific instructions for those. As a DSP noob I thought you could code an FFT using the basic instructions?
Also take a look at the newer FXCore chip from Experimental Noize as it is probably more powerful but it does require external CODECs which the FV-1 has built-in.
also no examples to do so, DSP without dedicated FFT/iFFT instructions is gonna be challenging
I am pretty sure I already have samples of these ship, I had them a while ago when the company was called wavefront or something
thanks anyway
OK I guess it's not going to do what you want but it is amazing how much you can squeeze out of those 128 instructions, albeit not a FFT!
The chip was the design of the late Keith Barr who founded Alesis and MXR before setting up Spin SemiConductor to manufacture the FV-1.
Did you say you had considered the Teensy? I know it's a module not a chip but it's very small and powerful and well-supported with audio libraries. There is also an Audio System Design Tool (drag and drop) which includes a couple of FFT modules. I grabbed a snippet of the screen and there's more details here
hence this thread
indeed there is a nice audio designer, which makes it silly the ADC's are not up to the level of the rest of the board/software...the ADC on the teensy are horsesh!t (50% SNR)
teensy 4.0 is more recent but has the same issue AFAIK
they suggested to hook up an I2S breakout board, but I was not lucky doing so, I get audio cracks cos the clock is jittering (20Mhz) and I got fed up with it
LOL Yes, agreed the ADCs are indeed what you say though I don't think mine was as bad as 50% SNR!
Best of luck finding something suitable,
Phil.
I built a whole device around the teensy
even made a .NET app communicating with it through usb to display the different stages of the signal processing
can't tell you how disgusted I was
well thanks for the help in any case...
Phil
