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Raspberry Pi Zero 2 W

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Re: Raspberry Pi Zero 2 W

#81

Post by hadlock »

LeanderK wrote: post #64

How long before cutting edge hardware trickles down to stuff like the Pi Zero? I think a usb-c port would be more useful for these small form-factors, but it's probably a long way of considering there's only usb 2.0.

Yep lack of a USB-C power port is a no-go from my perspective. I only have a handful of micro usb cables left in the house, not interested in adding more at this point. Even the cheap terrible LED mini projectors, and high end Kindle e-readers have all switched over to USB-C for power. Strange to see micro usb on a Brand New Product in Q4 2021.

Re: Raspberry Pi Zero 2 W

#82

Post by scottlamb »

PragmaticPulp wrote: post #76
luegen wrote: post #74

Surprised nobody has mentioned or compared it to the Radxa Zero.[0][1] Spec of the Radxa Zero ($15): CPU: Quad Cortex-A53 1.8 GHz, 12nm process GPU: Mali G31 MP2 RAM: LPDDR4 512MB/1GB/2GB/4GB Storage: eMMC 5.1 8/16/32/64/128GB and uSD card HDMI: Micro HDMI, HDMI 2.1, 4K@60 HDR Multimedia: H265/VP9 decode 4Kx2K@60 Wireless: WiFi4/BT4 or WiFi5/BT5 USB: One USB 2.0 Type C OTG, one USB 3.0 Type C host GPIO: 40Pin GPIO, A…

> The Radxa seems to be better value. The Radxa is a better value if pure performance is the only criteria. But the real value of the Raspberry Pi products is the ecosystem and code support. It will be much easier to find tutorials and software support for the Pi Zero 2 W than the Radxa and the Pi will be supported for a long time after the Radxa has been discontinued.

> But the real value of the Raspberry Pi products is the ecosystem and code support.

Also in availability. I just clicked buy and will have a Raspberry Pi Zero 2 W shipping to me in two days. I looked on seeedstudio for Radxa products; literally nothing is in stock.

Re: Raspberry Pi Zero 2 W

#83

Post by MisterTea »

idiotsecant wrote: post #70
MisterTea wrote: post #58

Earlier quoted context omitted.

RS485 is just an electrical standard for serial transmission that includes multiple devices on the same bus. It is not a network or transport protocol. I doubt SLIP would function on an RS485 connection as 485 is typically used in master-slave configurations where only one master unit sends messages and listening "slave" devices only respond if addressed. You'd have to write a protocol layer to handle the transport o…

or just use the standard rs485 protocol that all industrial hardware has used for decades and has preexisting nice libraries - modbus. Built in CRC, dirt simple, reliable.

I know modbus very well. The OP was talking about networking the machines using SLIP over 485 which is completely different than moving around bits and words.

Re: Raspberry Pi Zero 2 W

#84

Post by oblio »

LeanderK wrote: post #64

How long before cutting edge hardware trickles down to stuff like the Pi Zero? I think a usb-c port would be more useful for these small form-factors, but it's probably a long way of considering there's only usb 2.0.

Apparently this has it: https://forum.radxa.com/t/introduce-the-radxa-zero/6550

Re: Raspberry Pi Zero 2 W

#85

Post by scottlamb »

bullen wrote: post #28
geerlingguy wrote: post #20

Earlier quoted context omitted.

Yes; check my blog post [1] or latest YouTube video [2] for details, but the tldr is 0.4W (80 mA) idle minimum for Zero W, 0.6W (100 mA) idle minimum for Zero W 2. Zero W goes up to 160 mA at load, while Zero W 2 gets up to 400-500 mA due to the three extra CPU cores. [1] https://www.jeffgeerling.com/blog/2021/look-inside-raspberry... [2] https://www.youtube.com/watch?v=lKS2ElWQizA

2W! Did you measure Gflops? I wish you could disable cores dynamically...

> I wish you could disable cores dynamically...

Another comment says /sys/devices/system/cpu/cpu[0-n]/online doesn't work, but I think you can get pretty far by changing the CPU affinity at the cgroup or process levels (for userspace) and on /proc/irq/default_smp_affinity (for interrupts). There are likely some kernel threads that would still run on the other cores, but this is reasonably close.

In particular, looks like setting CPUAffinity= /etc/systemd/system.conf will set a default for all of userspace that you can override for particular things as desired.

Re: Raspberry Pi Zero 2 W

#86

Post by cmurf »

chronogram wrote: post #45
oxplot wrote: post #33

Earlier quoted context omitted.

As for the RAM limitation, zswap is a great way to get some more RAM at cost of some CPU cycles which on the new Pi won't be an issue.

zram* zram is the compress-in-memory like you have in Windows and ChromeOS and zswap is the compress-on-disk in case you want to replace SD cards.

zram is a compressed ram-disk that acts like any other block device, so you can point `mkswap` and `swapon` at it.

zswap is a compressed (memory) cache that uses the frontswap API to evict least recently used pages to a swap device. Evicted pages are not compressed.

zram is more of a general purpose component; whereas zswap is a more specialized component.

https://www.kernel.org/doc/Documentation/blockdev/zram.txt https://www.kernel.org/doc/html/latest/vm/zswap.html

Re: Raspberry Pi Zero 2 W

#87

Post by cwiggs »

luegen wrote: post #74

Surprised nobody has mentioned or compared it to the Radxa Zero.[0][1] Spec of the Radxa Zero ($15): CPU: Quad Cortex-A53 1.8 GHz, 12nm process GPU: Mali G31 MP2 RAM: LPDDR4 512MB/1GB/2GB/4GB Storage: eMMC 5.1 8/16/32/64/128GB and uSD card HDMI: Micro HDMI, HDMI 2.1, 4K@60 HDR Multimedia: H265/VP9 decode 4Kx2K@60 Wireless: WiFi4/BT4 or WiFi5/BT5 USB: One USB 2.0 Type C OTG, one USB 3.0 Type C host GPIO: 40Pin GPIO, A…

That's an interesting setup, I'd love to hear more. Do you have a wifi antenna hooked up to the pi?

Re: Raspberry Pi Zero 2 W

#88

Post by rbanffy »

geerlingguy wrote: post #79
rbanffy wrote: post #53

Earlier quoted context omitted.

`echo 0 > /sys/devices/system/cpu/cpu[0-n]/online` should do what you want.

Even as root, that gives `permission denied` on Pi OS on the Zero 2 W. I'm trying the kernel cmdline option too. Edit: That works! See: https://www.jeffgeerling.com/blog/2021/disabling-cores-reduc...

Well… I said it should, not that it would. ;-)

Re: Raspberry Pi Zero 2 W

#89

Post by giantrobot »

throwaway81523 wrote: post #22
jwoglom wrote: post #3

Earlier quoted context omitted.

Definitely seems a bit disappointing that 5-6 years after the original Pi Zero there's still only 512MB of RAM. Regardless, I'm excited to see what new projects will become feasible with the extra CPU performance. I just finished watching your YouTube video, so thanks for providing all of this insight. A new Pi Zero will certainly make small handheld emulators a lot more promising...

I don't feel like I needed more memory or the cpu boost in the pi zero 2. I'd rather they stayed at the old $5 price, decreased power consumption, and added some analog and realtime capabilities. I had thought that was the idea of the RP2440 chip used in the pi pico. It would be great if they added that chip to a pi zero board (maybe in the same SOC as the main processor) so they would have some analog inputs and a s…

Power savings is complicated. A Pi board is going to have a minimum power usage with the CPU only being a portion. A lower clocked CPU on a Pi -1 might reduce peak power usage but might not get much savings at idle vs a comparably configured Zero. The Zero would also have the option of underclocking for peak power savings with the ability to spin back up to work faster to return to idle faster. Don't forget disabling board components can yield baseline power savings on Pis [0].

[0] https://mlagerberg.gitbooks.io/raspberry-pi/content/5.1-powe...

Re: Raspberry Pi Zero 2 W

#90

Post by jiggunjer »

throwaway81523 wrote: post #22
jwoglom wrote: post #3

Earlier quoted context omitted.

Definitely seems a bit disappointing that 5-6 years after the original Pi Zero there's still only 512MB of RAM. Regardless, I'm excited to see what new projects will become feasible with the extra CPU performance. I just finished watching your YouTube video, so thanks for providing all of this insight. A new Pi Zero will certainly make small handheld emulators a lot more promising...

I don't feel like I needed more memory or the cpu boost in the pi zero 2. I'd rather they stayed at the old $5 price, decreased power consumption, and added some analog and realtime capabilities. I had thought that was the idea of the RP2440 chip used in the pi pico. It would be great if they added that chip to a pi zero board (maybe in the same SOC as the main processor) so they would have some analog inputs and a s…

I think you'd need a SoC designed for phones instead of general computing to reduce power by that much.

Also, I'm curious what use-case do you have that would need an RTOS?

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