[offtopic]Some cheap and tiny ARM devices.

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marcov
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Re: [offtopic]Some cheap and tiny ARM devices.

Postby marcov » Sep 22, 2017 20:33

D.J.Peters wrote:
marcov wrote:If you smell something burning, the voltage is too high :-)
No A=ampere makes a hot dog not the V=voltage ;-)


Well, unless you have a special kind of dog that has a resistance that changes with potential, the current will rise if you up the potential.

With other words you can touch 100,000 V with 0.1 A without any problems but never touch 0.1V with 100,000 A !


I'm no physicist, merely an ex-chemist, but at high potentials be careful, specially if they are generated by a big(ger) charge and are thus not quickly depleted.

The field of such potentials might do icky things with materials changing resistance and thus current. The field might even interfere with the signals from your brain to your heart, which are generally considered a good thing to have (also in dogs, so keep the 100000V away from him)
srvaldez
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Re: [offtopic]Some cheap and tiny ARM devices.

Postby srvaldez » May 28, 2020 19:56

the Raspberry PI4 just got a memory upgrade to 8GB https://www.pishop.us/product-category/ ... -pi-4-8gb/
also the work has begun on Raspberry Pi OS 64-bit https://www.raspberrypi.org/forums/view ... 7&t=275370
I ordered a 8GB PI4 with desktop bundle for $140 + 14.95 for shipping & handling
caseih
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Re: [offtopic]Some cheap and tiny ARM devices.

Postby caseih » May 29, 2020 0:01

Am I the only one who is constantly disappointed by these ARM SoC devices? They hold such promise but are held back by proprietary firmwares, strange boot systems, and a general lack of standards that prevent me from taking a generic linux distro and just installing it like I do on any x86 hardware. It's very discouraging how much doesn't work very well. Instead you get a bunch of pseudo distributions that cater to each SoC. Other features are often missing too. In particular the Pi is completely missing anything resembling power management. You can't shut itself down from a script, for example, and then power it up with a signal from a low-power microprocessor. OpenGL ES acceleration is hit and miss. Some distros have it, others don't. Ubuntu 20.04 officially supports the Pi 3 and 4 (in full 64-bit mode no less) but alas, no V3D driver support there, although Mesa has the bits to work with it. Guess the kernel driver is too experimental.

I've got a Pine64 that I'm currently using as a mini server, and that hardware (everything from Pine64) holds a lot of promise, including proper power management. But here again, the lack of open source drives for proprietary hardware bites us. No easy, out-of-the-box way to get opengl drivers working, and in fact I can barely get any GUI desktop to work on it. So much for x86 replacement.

I tried running an ARM SoC a few years ago as my main router and firewall. But that proved to be too difficult for me to maintain (uboot ugg). So now I run a little x86 box the size of a cassette tape. Pricey but functional.

Seriously if Intel could figure out a way to make a chip that competed in the same computing power per watt realm as ARM, they'd stomp all over ARM. I want to love ARM. I really do. But so far I just can't. Even though I keep buying the new boards hoping things are better... and they never are. I'm probably going to buy the 8GB Pi in the vain hope it can be a little workstation for me in the office. I never learn I guess.
D.J.Peters
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Re: [offtopic]Some cheap and tiny ARM devices.

Postby D.J.Peters » Aug 23, 2020 19:37

The new revision of the older "ODROID N2" is out the "ODROID N2+"
2 or 4GB, 4 x USB3, Audio/Video out, HDMI 2.0 up to 4K 60 FPS, Quad-core Cortex-A73 + Dual-core Cortex-A53
4 x 2.4 GHz + 2 x 2 GHz = 13.6 GHz stress test only 6.2W power consumption = 0.455W per GHz !!!

youtube: Odroid N2+ Full Linux Review

hardkernel: ODROID-N2+ with 4GByte RAM $79.00

Joshy
TJF
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Re: [offtopic]Some cheap and tiny ARM devices.

Postby TJF » Sep 06, 2020 9:01

@caseih

I'm not disappointed by ARM SoC devices. But I don't see them as a replacement for desktop computers. Instead I use them for real-time closed-loop-controllers.

I'm speaking about the BeagleBone series (White, Black, Green, Blue, Poket). The ARM335x CPU contains two PRUSS (Programmable Realtime SubSystems), which are perfect to do real-time programming. One for input/output, the other for the controller loop. My library libpruio makes system configuration as easy as on Arduino systems, but on a full featured LINUX system.

Sure, if I'd be limited to the kernel hardware support (GPIO, eCAP, ADC, PWM, TIMER, ..), I wouldn't love the system either.

Regards
D.J.Peters
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Re: [offtopic]Some cheap and tiny ARM devices.

Postby D.J.Peters » Mar 20, 2021 22:49

!!! The Raspberry foundation created it's own 4$ ARM M0+ dual core micro controller with 133 MHz and 256K SRAM !!!

Infos about the RP2040: https://www.raspberrypi.org/documentati ... g-started/
PI PICO board https://www.raspberrypi.org/products/raspberry-pi-pico/

all about the programable high speed IO pins: https://www.youtube.com/watch?v=yYnQYF_Xa8g

one crasy feature in scope of I/O pin programing are the loop jump does not use a program cycle !

pseudo code

loop:
pin 1,0
pin 1,1
jump loop

On all other MC's it will produce a square wave like this
|| || || || ||
the duty cicle istn't 50% becourse 1 cycle low 1 cycle high and one more cycle for the jump instruction !

On the RP2040 it's a clean square wave 1 cycle low 1 cycle high no cycle for the repeat instruction.
||||||||||

Joshy

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