Go to advanced search

by Gnyueh
Fri Jan 08, 2021 10:47 am
Forum: Beginners
Topic: Is it possible to control the stock fan via PWM?
Replies: 11
Views: 430

Re: Is it possible to control the stock fan via PWM?

If anybody is interested, I have set up a temperature compensating PWM fan on my Pi 4. The same technique should work on any Pi. The basic circuit is as described in this article https://www.instructables.com/PWM-Regulated-Fan-Based-on-CPU-Temperature-for-Ras/ I used a 5v 30mm x 30mm x 7mm fan (eba...
by Gnyueh
Fri Jan 08, 2021 9:30 am
Forum: Beginners
Topic: Is it possible to control the stock fan via PWM?
Replies: 11
Views: 430

Re: Is it possible to control the stock fan via PWM?

@Gnyueh Have you a link to the fan you are using? How have you wired it up? The fan is just raspberry pi 4 case fan https://www.raspberrypi.org/products/raspberry-pi-4-case-fan/ and it works basically fine with software PWM. There are very limited variants of PWM fan at that size. I also found anot...
by Gnyueh
Wed Jan 06, 2021 2:40 pm
Forum: Beginners
Topic: Is it possible to control the stock fan via PWM?
Replies: 11
Views: 430

Re: Is it possible to control the stock fan via PWM?

The last time I looked at this the stock overlay (dtoverlay=gpio-fan) did not use PWM. It simply switched the fan on when a temperature was reached. I think the specs for a proper PC fan (four wire, controlled via the PWM input) require 25 kHz PWM and a funny ramp up. Perhaps .those specs no longer...
by Gnyueh
Wed Jan 06, 2021 2:37 pm
Forum: Beginners
Topic: Is it possible to control the stock fan via PWM?
Replies: 11
Views: 430

Re: Is it possible to control the stock fan via PWM?

I would be pretty certain that @davidcoton's reply was in respect of this RaspberryPi-branded product - https://www.raspberrypi.org/products/raspberry-pi-4-case-fan/ Correct. Is there a misunderstanding about what you are trying to accomplish? Surely a simple fan does not need the precision implied...
by Gnyueh
Tue Jan 05, 2021 12:11 pm
Forum: Beginners
Topic: Is it possible to control the stock fan via PWM?
Replies: 11
Views: 430

Re: Is it possible to control the stock fan via PWM?

If by "stock fan" you mean the RPT fan for the Pi4B housing, then yes. Thanks a lot, I read Intel's specification for PWM fan and it says the typical PWM frequency is 25kHz. I think I need use the hardware PWM to generate PWM wave at such frequency. Is there any library available to contr...
by Gnyueh
Tue Jan 05, 2021 10:47 am
Forum: Beginners
Topic: Is it possible to control the stock fan via PWM?
Replies: 11
Views: 430

Is it possible to control the stock fan via PWM?

Is it possible to control the speed of stock fan via PWM?
by Gnyueh
Sun Nov 15, 2020 8:32 am
Forum: General discussion
Topic: For now, is it possible to use triple screen simultaneously on raspi 4?
Replies: 0
Views: 97

For now, is it possible to use triple screen simultaneously on raspi 4?

A previous thread about triple screen support: https://www.raspberrypi.org/forums/viewtopic.php?t=243812 Not currently, but the hardware potentially could feed 3 devices simultaneously. There are 3 HVS (Hardware Video Scalar) channels, which each feed into one of the 5 pixel valves at a time, and fr...
by Gnyueh
Fri Nov 13, 2020 2:39 pm
Forum: General discussion
Topic: Possibility of power and data(as host) through C port on RPi4
Replies: 2
Views: 135

Re: Possibility of power and data(as host) through C port on RPi4

rpdom wrote:
Fri Nov 13, 2020 2:27 pm
Gnyueh wrote:
Fri Nov 13, 2020 2:13 pm
But is it possible to use an otg wire with external power supply to get both:?:
Yes.
Short but the most valuable answer! Thanks a lot for your reply and I am going to order an otg wire.
by Gnyueh
Fri Nov 13, 2020 2:13 pm
Forum: General discussion
Topic: Possibility of power and data(as host) through C port on RPi4
Replies: 2
Views: 135

Possibility of power and data(as host) through C port on RPi4

Is there possibility of both powering RPi4 through C port and using it as an additional USB port to connect something like a keyboard? I go through some early discussion about this. It seems that you have to choose between power and data(as host) for the C port. But is it possible to use an otg wire...
by Gnyueh
Mon Aug 03, 2020 11:33 am
Forum: General discussion
Topic: USB speed after moving from RPi 3 B to RPi 4
Replies: 3
Views: 321

Re: USB speed after moving from RPi 3 B to RPi 4

I have been running Raspbian Buster on a Raspberry Pi 3 B for over a year and got a RPi 4 4GB recently. I cloned the SD card and moved the SSD from the 3 to 4. Everything seems to be fine except the speed. If I put the SSD on one of the USB 2 ports, the speed is similar to I used to wtih the RPi 3....
by Gnyueh
Sun Aug 02, 2020 1:44 pm
Forum: General discussion
Topic: RPi4 BCM2711 and ARMv8 Crypto Extensions?
Replies: 61
Views: 9277

Re: RPi4 BCM2711 and ARMv8 Crypto Extensions?

I think focusing this is off the topic and it would be better to discuss something like ”why crypto extension improves throughout of AES much better than the latency“ Only if it is directly relevant to the Pi, and I think we are pretty much done with discussing that idea: No current Pi CPU has hard...
by Gnyueh
Sun Aug 02, 2020 11:56 am
Forum: General discussion
Topic: RPi4 BCM2711 and ARMv8 Crypto Extensions?
Replies: 61
Views: 9277

Re: RPi4 BCM2711 and ARMv8 Crypto Extensions?

Thanks a lot for your remind, this is a common way to avoid read text unless you select it. I don't understand, why would anyone want to make an honest post difficult to read? Same with a transliterated Greek(?) sig which Google can't/won't translate. It does not help your credibility. If you want ...
by Gnyueh
Sun Aug 02, 2020 10:30 am
Forum: General discussion
Topic: RPi4 BCM2711 and ARMv8 Crypto Extensions?
Replies: 61
Views: 9277

Re: RPi4 BCM2711 and ARMv8 Crypto Extensions?

Gnyueh, could you please not randomly change the font colour of paragraphs? Especially changing it to white as that makes it nigh on impossible to read being as the background is very light blue on the prosilver theme (I assume it is more readable on another theme). Really there is no reason to cha...
by Gnyueh
Sun Aug 02, 2020 10:20 am
Forum: General discussion
Topic: RPi4 BCM2711 and ARMv8 Crypto Extensions?
Replies: 61
Views: 9277

Re: RPi4 BCM2711 and ARMv8 Crypto Extensions?

I have edited out the colour changes in the post above. I have no idea why they were there, it just made the text invisible on my screen. This is a common technique used by spammers, so unless you want to be treated the same way as spammers are treated, I'd suggest different ways of highlighting - ...
by Gnyueh
Sun Aug 02, 2020 5:48 am
Forum: General discussion
Topic: RPi4 BCM2711 and ARMv8 Crypto Extensions?
Replies: 61
Views: 9277

Re: RPi4 BCM2711 and ARMv8 Crypto Extensions?

crc and simd are mandatory to call it a armv8... so every A72 core on earth will have them and most will have armv8 cryptoextensions as well, from the dirt cheap allwinner A64 over every rockchip 64bit SoC I know to all newer amlogic SoCs I know... afaik only some of the older amlogic stuff didn't ...
by Gnyueh
Fri Jul 31, 2020 5:34 pm
Forum: General discussion
Topic: RPi4 BCM2711 and ARMv8 Crypto Extensions?
Replies: 61
Views: 9277

Re: RPi4 BCM2711 and ARMv8 Crypto Extensions?

I'm trying to find out how much faster the NEON implementation is and whether its available on 32 and 64 bit. Only figure found so far is about 75% but that is from an old paper on the pi3B. Page 94 https://www.researchgate.net/publication/339243728_Fast_AES_Implementation_Using_ARMv8_ASIMD_Without...
by Gnyueh
Fri Jul 31, 2020 5:24 pm
Forum: General discussion
Topic: Actual memory bandwidth of raspberry pi4?
Replies: 75
Views: 4917

Re: Actual memory bandwidth of raspberry pi4?

jamesh wrote:
Fri Jul 31, 2020 5:22 pm
Gnyueh wrote:
Fri Jul 31, 2020 4:36 pm
For RPi4 I think it is basically VC6's fault.
You may think that. We don't.
Whatever, you are under NDA and cannot say anything more anyway.
by Gnyueh
Fri Jul 31, 2020 4:44 pm
Forum: General discussion
Topic: RPi4 BCM2711 and ARMv8 Crypto Extensions?
Replies: 61
Views: 9277

Re: RPi4 BCM2711 and ARMv8 Crypto Extensions?

But you also denied that USB3 or a proper GbE is a thing till the pi had it.. Or with more than 1GB ram etc (fun fact RPi is now the SBC offering most ram in the low price league :lol: ). Really? I'm pretty sure I knew those tings existed before they appeared on the Pi4. Worth noting that we NEVER ...
by Gnyueh
Fri Jul 31, 2020 4:36 pm
Forum: General discussion
Topic: Actual memory bandwidth of raspberry pi4?
Replies: 75
Views: 4917

Re: Actual memory bandwidth of raspberry pi4?

I cannot be particularly detailed (NDA), but it worth noting that everyday memory bandwidth usage will, on average, be higher than pathological test case memory tests seen here. We would probably expect anywhere between 20 and 40% better performance in real world usage than that show in some memory...
by Gnyueh
Fri Jul 31, 2020 3:19 pm
Forum: General discussion
Topic: Actual memory bandwidth of raspberry pi4?
Replies: 75
Views: 4917

Re: Actual memory bandwidth of raspberry pi4?

I cannot be particularly detailed (NDA), but it worth noting that everyday memory bandwidth usage will, on average, be higher than pathological test case memory tests seen here. We would probably expect anywhere between 20 and 40% better performance in real world usage than that show in some memory...
by Gnyueh
Fri Jul 31, 2020 3:12 pm
Forum: General discussion
Topic: Actual memory bandwidth of raspberry pi4?
Replies: 75
Views: 4917

Re: Actual memory bandwidth of raspberry pi4?

another factor i heard about on irc, is that the dram cant transfer at the full rate you would assume, from just bus_width * clock because a certain percentage of the time is taken up by dram refresh cycles and there is a certain number of clock cycles you must wait for, every time you open a new r...
by Gnyueh
Fri Jul 31, 2020 3:05 pm
Forum: General discussion
Topic: Actual memory bandwidth of raspberry pi4?
Replies: 75
Views: 4917

Re: Actual memory bandwidth of raspberry pi4?

https://gist.github.com/cleverca22/84b731d904ad185e3913a773f895601f this is the logs from BOOT_UART=1 in bootconf.txt with a 4gig pi4, of note is this line: Initialising SDRAM 'Micron' 16Gb x2 total-size: 32 Gbit 3200 i believe the 3200 here is the clock speed its running the dram at Thanks a lot f...
by Gnyueh
Fri Jul 31, 2020 2:52 pm
Forum: General discussion
Topic: Actual memory bandwidth of raspberry pi4?
Replies: 75
Views: 4917

Re: Actual memory bandwidth of raspberry pi4?

I think the chip is rated for 3200 MHz but is only run at 2400 MHz, possibly due to limitations in the SOC or routing on the circuit board. Indeed, the memory bus on the 4B is noticeably slower than the same on many other computers. At the same time, the price is noticeably cheaper. https://gist.gi...
by Gnyueh
Fri Jul 31, 2020 2:42 pm
Forum: General discussion
Topic: Actual memory bandwidth of raspberry pi4?
Replies: 75
Views: 4917

Re: Actual memory bandwidth of raspberry pi4?

I guess in the subpages specifically about the processors. Not really thought about it yet. In that page supported memory speed is reported as 2400MHz while according to some discussion in the forum the speed is 3200MHz...... I think the chip is rated for 3200 MHz but is only run at 2400 MHz, possi...
by Gnyueh
Fri Jul 31, 2020 11:12 am
Forum: General discussion
Topic: Actual memory bandwidth of raspberry pi4?
Replies: 75
Views: 4917

Re: Actual memory bandwidth of raspberry pi4?

I guess in the subpages specifically about the processors. Not really thought about it yet. In that page supported memory speed is reported as 2400MHz while according to some discussion in the forum the speed is 3200MHz...... https://www.raspberrypi.org/forums/viewtopic.php?f=63&t=263562&p=...

Go to advanced search