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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: 119

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: 16
Views: 234

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: 49

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: 60

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: 94
Views: 7589

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: 8
Views: 247

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: 9
Views: 202

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: 94
Views: 7589

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: 98

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: 28

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: 5
Views: 84

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: 68

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...
by trejan
Sat Sep 14, 2019 1:36 pm
Forum: Troubleshooting
Topic: USB not detected
Replies: 3
Views: 68

Re: USB not detected

You need to put a USB hub between the Pi 4 and the Aeotech Z-Stick. The Z-Stick does something non-compliant with USB and confuses the USB controller. Read https://github.com/raspberrypi/linux/issues/3027 for more information and some hubs that other people have tested. Not all USB hubs work.
by trejan
Sat Sep 14, 2019 1:49 am
Forum: General discussion
Topic: [SOLVED] Pi4 won't boot after update + no usb ports
Replies: 3
Views: 231

Re: Pi4 won't boot after update + no usb ports

GPIO0 and GPIO1 are used for the HAT configuration EEPROM. The firmware will try to read the EEPROM at startup to load in any configuration. Those two pins being connected to ground via your sensors is causing that to fail. GPIO pins ID_SC and ID_SD (GPIO0 and GPIO1) are reserved for use solely for ...
by trejan
Fri Sep 13, 2019 10:55 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: I2C6
Replies: 4
Views: 123

Re: I2C6

The additional peripherals in the Pi 4 are all listed in https://github.com/raspberrypi/linux/bl ... m2838.dtsi
by trejan
Fri Sep 13, 2019 9:30 pm
Forum: General discussion
Topic: Upgraded Pi2 to 3 CPU limits unchanged
Replies: 3
Views: 199

Re: Upgraded Pi2 to 3 CPU limits unchanged

Why does cpuinfo report I have a BCM2835? The upstream Linux kernel developers had decided that all models of Raspberry Pi return bcm2835 as the SoC name. At Raspberry Pi we like to use as much upstream kernel code as possible, as it makes software maintenance much easier, so we use this code. Unfo...
by trejan
Fri Sep 13, 2019 8:07 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: I2C6
Replies: 4
Views: 123

Re: I2C6

0x7E205C00

AFAIK it is exactly the same I2C peripheral as the others so the registers should be all the same.
by trejan
Fri Sep 13, 2019 12:51 pm
Forum: Graphics, sound and multimedia
Topic: Rpi4 encode HEVC
Replies: 1
Views: 77

Re: Rpi4 encode HEVC

H.265 acceleration is decode only on the Pi 4.
by trejan
Thu Sep 12, 2019 11:28 am
Forum: General discussion
Topic: Back Voltage from USB Hub
Replies: 8
Views: 281

Re: Back Voltage from USB Hub

Burngate wrote:
Thu Sep 12, 2019 10:06 am
The B+ had a AP2553 acting as a reverse-current blocking device.
Apparently the 4B does not.
4B has an AP2552 which is an active low enable version of the AP2553.
by trejan
Thu Sep 12, 2019 3:24 am
Forum: Troubleshooting
Topic: VLI firmware v2.0 - powersaving features enabled
Replies: 55
Views: 3248

Re: VLI firmware v2.0 - powersaving features enabled

Is vl805 utility itself closed source (proprietary)? Are its sources available anywhere? Closed source. I'm not sure who wrote it. The VL805 documentation is only available under NDA and the vl805 tool does do some undocumented register twiddling so there might be a problem releasing it. You need t...
by trejan
Thu Sep 12, 2019 3:02 am
Forum: Troubleshooting
Topic: Does Pi 4 support stereo sound?
Replies: 1
Views: 81

Re: Does Pi 4 support stereo sound?

iammer wrote:
Thu Sep 12, 2019 2:18 am
Does the Pi4 support stereo sound? Seems like it should but mine always reports mono.
The Pi supports stereo. The volume control is listed as mono because you can't set the volume of the L + R channels independently.
by trejan
Wed Sep 11, 2019 5:31 pm
Forum: Beginners
Topic: Was it always possible to control addressable LEDs with a Pi?
Replies: 5
Views: 118

Re: Was it always possible to control addressable LEDs with a Pi?

Also, you'll find lots of articles saying you need level-shifters to drive them but I've never done so and not had a problem It usually works but there is no guarantee. You're violating the published specifications of the WS2812 if you do this. The datasheet says input high is 0.7 x Vdd which means...
by trejan
Wed Sep 11, 2019 5:24 pm
Forum: Troubleshooting
Topic: woeful throughput on pi as raspbian router
Replies: 23
Views: 469

Re: woeful throughput on pi as raspbian router

I can see in a tcpdump that pulling something down from the net I get some huge frames, 16kb etc., A 16KB frame from where? If it is coming from the Internet then you need to check it again as that isn't usually possible. Jumbo frames are usually restricted to your local network only as virtually a...

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