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by trejan
Fri Sep 20, 2019 1:08 am
Forum: Advanced users
Topic: USB 3.0 OTG?
Replies: 4
Views: 110

Re: USB 3.0 OTG?

Not possible on the Pi 4. The VL805 USB controller doesn't support device mode or OTG. There is a disabled XHCI controller inside the SoC but it is host only and only 2 data lines are connected anyway so it can only run at USB 2.0 speeds. I couldn't get it to work last time I tried so YMMV. The defa...
by trejan
Thu Sep 19, 2019 1:11 am
Forum: Troubleshooting
Topic: What prevents a 'sudo reboot' ?
Replies: 6
Views: 161

Re: What prevents a 'sudo reboot' ?

Are those photos kept on another server somewhere else? If so, is it hanging trying to unmount the share/export?

It will have killed sshd before the unmount step which is why you can't log into it.
by trejan
Wed Sep 18, 2019 2:17 pm
Forum: Device Tree
Topic: RPi4 Ethernet LED control
Replies: 2
Views: 75

Re: RPi4 Ethernet LED control

The VL805 chip is only a USB controller. Ethernet is separate on the Pi 4 with the MAC inside the SoC and an external PHY. The external PHY doesn't have any public documentation so AFAIK there is no way of turning off the LEDs yet. The config.txt option and the utility are for the 3B+ and older mode...
by trejan
Wed Sep 18, 2019 12:52 pm
Forum: Beginners
Topic: Can you turn off the pi 4 pwr and Ethernet lights?
Replies: 2
Views: 83

Re: Can you turn off the pi 4 pwr and Ethernet lights?

No known way of turning off the Pi 4 Ethernet socket LEDs. The LEDs are wired to the Broadcom Ethernet PHY and there is no public documentation on it AFAIK. The config.txt options to turn off the LED is only for the 3B+ and the utility is for the older Pi boards.
by trejan
Wed Sep 18, 2019 12:48 pm
Forum: Troubleshooting
Topic: USB Blown is there any USB output on GP10.
Replies: 14
Views: 277

Re: USB Blown is there any USB output on GP10.

As other people have pointed out, there is no USB on the GPIO header. The chip you've blown up is a AP2553W6-7 . No guarantees replacing that switch will fix it. There may be damage to other components like the LAN7515 USB hub/Ethernet chip. It is GPIO not GP10 BTW. It stands for General-Purpose Inp...
by trejan
Wed Sep 18, 2019 12:39 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: PWM to 3.5mm jack
Replies: 7
Views: 146

Re: PWM to 3.5mm jack

MikeDB wrote:
Wed Sep 18, 2019 10:22 am
I'll take that as "a separate totally undocumented PWM chip for audio" :-) How the Pi became a world standard with such a poor level of documentation is quite amazing.
They're working on it. The BCM2711 peripheral documentation is coming soon.
by trejan
Tue Sep 17, 2019 9:19 pm
Forum: Compute Module
Topic: Compute Module 4
Replies: 7
Views: 377

Re: Compute Module 4

Perhaps if enough people here say they want one, that will encourage them to make one. They already know that people want a CM4 so threads like this aren't very productive. However, if you do actually use a lot of Compute Modules then you should submit feedback on https://www.raspberrypi.org/blog/h...
by trejan
Mon Sep 16, 2019 10:27 pm
Forum: General discussion
Topic: Pi 3b has Pi 3b+ Broadcom wifi/bt chip?
Replies: 8
Views: 311

Re: Pi 3b has Pi 3b+ Broadcom wifi/bt chip?

You can see the manufacturer list at https://www.raspberrypi.org/documentati ... /README.md

The Egoman, Embest, Qisda and Stadium factories are in China.
by trejan
Mon Sep 16, 2019 10:04 pm
Forum: General discussion
Topic: root password for Raspbian
Replies: 7
Views: 55757

Re: root password for Raspbian

really root is set to have no password even though it is an account that in theory can login ? No. The default is that it forbids all login attempts. It isn't a blank password which would let anybody log in without a password. Once you've manually set a password then you can log into the root accou...
by trejan
Mon Sep 16, 2019 9:55 pm
Forum: Beginners
Topic: [SOLVED] Is this fiberglass sticking out of my Pi's PCB?
Replies: 4
Views: 158

Re: Is this fiberglass sticking out of my Pi's PCB?

PCBs are made out of resin impregnated fiberglass sheets. When the boards are cut apart, you sometimes get a few wisps of fiberglass at the edge.

Just pull the strands off or carefully scrape the edge with something metal.
by trejan
Mon Sep 16, 2019 5:28 pm
Forum: Beginners
Topic: Help with automatic screen turn on/off
Replies: 2
Views: 69

Re: Help with automatic screen turn on/off

Turn off the official display:

Code: Select all

echo 1 > /sys/class/backlight/rpi_backlight/bl_power
Turn on the official display:

Code: Select all

echo 0 > /sys/class/backlight/rpi_backlight/bl_power
by trejan
Mon Sep 16, 2019 1:49 pm
Forum: Media centres
Topic: No signal to Pi 3+ with TV aerial splitter but ok with aerial cable direct?
Replies: 10
Views: 151

Re: No signal to Pi 3+ with TV aerial splitter but ok with aerial cable direct?

mihailolja wrote:
Mon Sep 16, 2019 1:48 pm
Surely the IN connector goes to the TV? Leaving one of the other connectors for the incoming aerial cable and the other for the Pi?
Signal from the antenna goes to IN and then splits into the two OUTs for the TV and Pi...
by trejan
Sun Sep 15, 2019 7:06 pm
Forum: C/C++
Topic: Output temp to Fahrenheit. Sub string hack but works
Replies: 4
Views: 153

Re: Output temp to Fahrenheit. Sub string hack but works

Using a double for this is overkill. A float is enough. char mystr[4]; mystr[0] = path[5]; mystr[1] = path[6]; mystr[2] = path[7]; mystr[3] = path[8]; //mystr[4] = '\0'; You need to increase mystr by 1 and also add the null terminator. atof will read off the end otherwise. You can skip creating myst...
by trejan
Sun Sep 15, 2019 4:52 pm
Forum: Media centres
Topic: SCART RGB output to old TV set
Replies: 23
Views: 410

Re: SCART RGB output to old TV set

I suspect the blanking input isn't making it change to RGB mode. Lack of combined sync might also be a problem but I'd expect something shown there even if it is not locked. They use a 75 ohm resistor because there is a 75 ohm pull down inside the TV. Use a multimeter to measure the voltage on that ...
by trejan
Sun Sep 15, 2019 4:08 pm
Forum: Beginners
Topic: cron vs datetime script
Replies: 2
Views: 60

Re: cron vs datetime script

If the message is to show it is running still then put it into your Python script. A cronjob will only show that the Pi is running and cron is working. The Python script could have died months ago but the cronjob wouldn't know anything about it.
by trejan
Sun Sep 15, 2019 6:00 am
Forum: Raspbian
Topic: [SOLVED] VLC displays videos only for "pi" user
Replies: 2
Views: 82

Re: VLC displays videos only for "pi" user

You need to add the extra users to the audio and video group.

Run "sudo adduser alice audio" and "sudo adduser alice video" then repeat for bob. They'll need to log out and log back in.
by trejan
Sun Sep 15, 2019 5:37 am
Forum: Advanced users
Topic: Pi4 64-bit raspbian kernel for testing - Focus on Pi4
Replies: 106
Views: 11076

Re: Pi4 64-bit raspbian kernel for testing - Focus on Pi4

I think the Raspberry Pi Engineers would get the benefit of more testers being attracted, and more tester contributions, such as discovering bugs . Hiring QA developers is not cheap, you know. Getting the loyal community to help out more is actually worth a lot, I say (and I am trying to encourage ...
by trejan
Sun Sep 15, 2019 2:59 am
Forum: Beginners
Topic: Am I running 32 or 64 bit ?
Replies: 9
Views: 342

Re: Am I running 32 or 64 bit ?

If you're running Raspbian then it'll be 32 bit. Run "uname -m" to confirm. If it says aarch64 then it is 64 bit. If it says armv7l then it is 32 bit.
by trejan
Sun Sep 15, 2019 2:27 am
Forum: Troubleshooting
Topic: [Not getting my full Gigabit internet speed on RPI 4b 4GB]
Replies: 15
Views: 366

Re: [Not getting my full Gigabit internet speed on RPI 4b 4GB]

You shouldn't bump posts after only a few hours.

The Debian packaged version of speedtest-cli is old and can give incorrect results. Uninstall the old version and update it using pip3.
by trejan
Sat Sep 14, 2019 11:36 pm
Forum: Advanced users
Topic: Pi4 64-bit raspbian kernel for testing - Focus on Pi4
Replies: 106
Views: 11076

Re: Pi4 64-bit raspbian kernel for testing - Focus on Pi4

Raspberry Pi Foundation could incentivize the discovery of more such performance gains (and shake out many new bugs in the transition to 64-bit) by offering a bounty of a new Raspberry Pi 4, 1GB model, with a power supply (a suitable rig for basic testing), shipped all-expenses paid, to any RPi 4-u...
by trejan
Sat Sep 14, 2019 6:28 pm
Forum: Beginners
Topic: Format the output of vcgencmd measure_clock arm to human readable value
Replies: 5
Views: 104

Re: Format the output of vcgencmd measure_clock arm to human readable value

vcgencmd measure_clock arm | awk ' BEGIN { FS="=" } ; { print $2 / 1000000000 "GHz" } '
If you want it rounded then do
vcgencmd measure_clock arm | awk ' BEGIN { FS="=" } ; { printf("%.1fGHz\n", $2 / 1000000000) } '
by trejan
Sat Sep 14, 2019 4:32 pm
Forum: Troubleshooting
Topic: No heirloom-mailx with Buster?
Replies: 1
Views: 32

Re: No heirloom-mailx with Buster?

The transitional heirloom-mailx package was removed. Use s-nail directly as all heirloom-mailx did was install s-nail + a symlink. If you don't want to update your scripts then create the symlink yourself.
by trejan
Sat Sep 14, 2019 2:48 pm
Forum: Other
Topic: my pi system time automatically goes to future DateTime, why?
Replies: 6
Views: 134

Re: my pi system time automatically goes to future DateTime, why?

What does "cat /etc/fake-hwclock.data" say?
by trejan
Sat Sep 14, 2019 2:10 pm
Forum: Troubleshooting
Topic: USB not detected
Replies: 3
Views: 83

Re: USB not detected

You could try adding max_usb_current=1 to config.txt and rebooting. Note this tests the power supply as it allows 1.2A over the USB compared to the default 600mA They're using a Pi 4. max_usb_current only did something on the Pi 2. The 3, 3+ and 4 are always set for 1.2A so completely ignore that o...

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