What's the cheapest way to get:
44kHz ADC > FFT > some light computation (e.g. 1000 multiplications) > IFFT > DAC
$1 Microcontrollers (2017)
81–90 of 103 posts
Re: $1 Microcontrollers (2017)
#82Earlier quoted context omitted.
ESP32 was released August 2016. I’m not even sure it was the first.
The ESP32 has two separate cores, not SMT. But look at the Parallax Propeller which goes back quite a long way. Also the Padauk is not exactly SMT afaict. It's more like time slicing. The idea of SMT in eg. an x86 is that one thread can run while another is blocked waiting for memory.
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Re: $1 Microcontrollers (2017)
#83Earlier quoted context omitted.
The ESP32 has two separate cores, not SMT. But look at the Parallax Propeller which goes back quite a long way. Also the Padauk is not exactly SMT afaict. It's more like time slicing. The idea of SMT in eg. an x86 is that one thread can run while another is blocked waiting for memory.
Sounds like a barrel processor [1], used to hide latency of individual instructions to allow code to be written without having to think as much about instruction scheduling / dependencies. [1] https://en.wikipedia.org/wiki/Barrel_processor
The Xmos chips give the programmer virtual time sliced contexts over one or more hardware core(s). Say you have a 400 Mhz base clock and 4 threads, each one would see the wall clock time advance at 100 Mhz. This is useful for having concurrent realtime operations on each hardware thread w/o having to resort to trickery.
These chips are ideal for DSP, phased arrays and beam forming. Most of their devkits are centered around voice applications.
https://www.xmos.ai/documentation/XM-014363-PC-5/html/arch-h...
https://www.xmos.ai/download/xCORE-Array-Microphone-Product-...
Re: $1 Microcontrollers (2017)
#84Maybe this is a dumb question, but are any of these cheap microcontrollers able to run Win 98? Or am I misunderstanding what microcontrollers can do?
Things called "microcontrollers" usually have these properties:
* They are actually CPUs, but with very weak feature sets related to desktop & scientific computing
* They may or may not have hardware to do any kind of advanced computation, starting with plain old multiplication and division of integers (addition and subtraction of integers is enough for what they do). Yes you read this correctly. The vast majority of 8-bit microcontrollers cannot even do division or even multiplication in hardware.
* They run with clocks from kilohertz to low megahertz
* They might be 8-bit, 16-bit or 32-bit, with rarity going up as the bitness goes up. There's a ton of 8-bit microntrollers, and 32-bit are much rarer. 64-bit ones are very very rare, since if you need that processing width, you might as well go for a single-board-computer like a Raspberry Pi.
* They are used to DIRECTLY drive other hardware, not in an abstract way. They literally regulate voltages on their pins to make stuff happen with connected hardware.
* They might have RAM space ranging from a couple of BYTES (yes, BYTES, see e.g. this one having 32 bytes of RAM: https://www.microchip.com/en-us/product/ATTINY9#) to a couple of hundreds of kilobytes. It's very rare to have a microcontroller with a megabyte or more of RAM, because, as before, in that case you might as well just use a full-featured desktop-ish CPU.
* They are usually lacking a special bit of hardware called a MMU (Memory Management Unit) which is used by "real" operating systems like Linux and Windows to manage process isolation and many other useful things related to memory. If you need a MMU, again, just use a SBC.
So where do we use microcontrollers? Well, what do you think happens in your garage or car keyfob when you click on the buttons? What tells your microwave when to finish and with which power level to nuke your food? What drives your electric toothbrush? Your car's gas valves? Microcontrollers, that's what.
They are currently (or have been a few years ago) so cheap we can readily add a microcontroller to every toilet paper leaf, and it would only bring the price of a roll up by a dollar or so. What's stopping us to do just that is the sorry state of current batteries and energy harvesting in general - those technologies simply are not as developed (yet).
So, no, you wouldn't describe a chip which can run Windows 98 as a "microcontroller".
Re: $1 Microcontrollers (2017)
#85Re: $1 Microcontrollers (2017)
#86What's the cheapest way to get: 44kHz ADC > FFT > some light computation (e.g. 1000 multiplications) > IFFT > DAC
Cheapest on what axis?
Qty 1, including your time, a raspberry pi zero.
Qty 1000, not including your time, an FPGA with embedded multipliers.
Re: $1 Microcontrollers (2017)
#87The author, Jay Carlson, is a really rad guy. I've got a few stereoscopic camera boards of his floating around that I happened to run into and a few emails later I had them up and running!
Re: $1 Microcontrollers (2017)
#88I've used a lot of micros as a hobbyist, and many on this list. For my time and money, I like the PSOC, even though the author pretty much dismisses them.
PSOC always seems to be what I need. I've used it to read CCDs (timing is very strict, and works much better on the SOC than in software). I've made capacitive soil moisture sensors using the capsense. The psoc5 has good options for USB devices.
But I don't make things to mass produce, so $1 has no appeal to me. $10 dev board is fine for me, if it does what I need it to do. There's a lot to love about the PSOC, but if you ignore all of the things they do that these other microcontrollers don't do, it might not look great by comparison. Also they have a development environment that is free and easy enough to learn that it doesn't require living in datasheets.
Re: $1 Microcontrollers (2017)
#89Earlier quoted context omitted.
Generally a microcontroller has no MMU. A microprocessor may mean the same thing. The industry term for something with an MMU is an application processor (Cortex-A). There are other terms that can be used, but it will need to be specified. There is some fuzzy area between MMU-less, small processors, and processors with no MMU but large enough to run Linux in a MMU-less way.
Interesting! Any idea how hard is it to include an MMU? Or better yet, what's the cheapest application processor?
It's not very hard at all. The issue is exclusively licensing fees.
Cheapest depends. There are Allwinner parts that are $2? But with the move to RISC-V, we will see costs decrease further, probably so that a Linux-capable part is just as expensive or cheaper than an MCU.
Whenever possible I reach for a part that can run Linux, because most of any embedded task nowadays is connectivity. A lot of parts include a microcontroller on the same die for realtime tasks.
Re: $1 Microcontrollers (2017)
#90The Texas Instruments MSP430 is another good one to look at. At one point, dev kits were available for under $10. It's a good choice for low-power applications. Comes with a free IDE.
I have been struggling to get TI's (free) Code Composer Studio to recognize my MSP430FR2311 boards now on-and-off for months. They 'upgrade' the code, and then I can't program my devices. In fact, so far, I've spent more time trying to get the dev environment to work than developing my code. Not Fun. Very cool when it does work, tho. I'd prefer to pay a little more for parts and get some English-based support. I'll w…
It helps if the USB cable one is using actually provides more than just Power and Ground. (red-faced blushing....)
I take back all the mud about CCS; except of course now it wants to put a new bootloader on one of the boards, but seems unable to do that. Good thing the other board is fine.