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by trejan
Sat Jul 13, 2019 3:43 pm
Forum: General discussion
Topic: Raspberry Pi 4 usb boot?
Replies: 574
Views: 227373

Re: Raspberry Pi 4 usb boot?

Gavinmc42 wrote: ↑
Sat Jul 13, 2019 8:22 am
it's peanuts for a new board regardless
Are you offering to pay for the PCB revision?
Read the rest of their reply as well. They mean buying a new RPi 4 board.
by trejan
Sat Jul 13, 2019 1:49 pm
Forum: Beginners
Topic: I want to connect an external antenna to Raspberry Pi Zero.
Replies: 11
Views: 1584

Re: What is it in Raspberry Zero ?

SaS1000 wrote: ↑
Fri Jul 12, 2019 6:06 pm
 I want to know what is the element selected in the picture and what should be done with it by connecting the external antenna?
RF filter.
by trejan
Sat Jul 13, 2019 12:45 pm
Forum: Troubleshooting
Topic: Raspberry Pi 4 - new VLI firmware issues
Replies: 69
Views: 30837

Re: Raspberry Pi 4 - new VLI firmware issues

More testing. There is definitely some other changes in the firmware that affect USB 2.0 as it isn't just turning on ASPM. Running usbtop with my USB 2.0 Airspy SDR set to 20MHz for ADS-B shows: Old firmware = 9230 kb/s New firmware + ASPM L0s/L1 = 2850 kb/s New firmware + ASPM L0s = 7552 kb/s New f...
by trejan
Sat Jul 13, 2019 11:02 am
Forum: General discussion
Topic: Why is an old Raspberry Pi shown as manufactured by Legra Systems?
Replies: 5
Views: 755

Re: Why is an old Raspberry Pi shown as manufactured by Legra Systems?

The Pi is only connected to the network via the above-mentioned WiFi dongle. It would seem unlikely that a new dongle would be using the MAC from a defunct company... Sometimes they're not programmed properly or they just don't care. For some really bad adapters, they don't even bother to add the E...
by trejan
Fri Jul 12, 2019 11:00 pm
Forum: Troubleshooting
Topic: GPIO 36 invalid channel? RPi4
Replies: 3
Views: 907

Re: GPIO 36 invalid channel? RPi4

RPi.GPIO needs an update for the RPi 4. Prerelease instructions here. It'll get pushed out as a regular update soon so you should be able to just wait for the update.
by trejan
Fri Jul 12, 2019 5:48 pm
Forum: General discussion
Topic: Why is an old Raspberry Pi shown as manufactured by Legra Systems?
Replies: 5
Views: 755

Re: Why is an old Raspberry Pi shown as manufactured by Legra Systems?

Legra Systems, Inc has nothing to do with Raspberry Pi and didn't manufacture your board. They got bought out by somebody else in 2004 and that company went out of business at the start of 2011 so they were long gone before the RPi even came out. Your scanning tool is picking up the odd MAC address ...
by trejan
Wed Jul 10, 2019 10:21 pm
Forum: Beginners
Topic: Is it a true ground?
Replies: 5
Views: 464

Re: Is it a true ground?

Using the RPi expansion header as the ground return path for something high current is a really bad idea and a good way of burning out traces or melting connectors. The return path for your external higher voltage/current devices should be a dedicated lead from your board to the PSU powering them.
by trejan
Wed Jul 10, 2019 9:44 pm
Forum: General discussion
Topic: RPi 4 : Lost GPIO-3 restart (and fix)
Replies: 34
Views: 15290

Re: RPi 4 : Lost GPIO-3 restart

andylh wrote: ↑
Wed Jul 10, 2019 1:35 pm
 Please revert to previous shutdown behaviour as soon as possible. I don't mind about not being in the lowest power level if I cannot restart.
timg236 already said how to revert it yourself in the post above yours?
by trejan
Wed Jul 10, 2019 8:50 pm
Forum: Beginners
Topic: ftp not installed or not working
Replies: 1
Views: 184

Re: ftp not installed or not working

The FTP client isn't part of the proftpd package. Do sudo apt-get install ftp and try again. ncftp is a lot nicer to use though so you may want to install that instead.
by trejan
Wed Jul 10, 2019 7:33 pm
Forum: Troubleshooting
Topic: Pi 4 fails to boot when active USB switch attached
Replies: 16
Views: 4356

Re: Pi 4 fails to boot when active USB switch attached

bromham wrote: ↑
Wed Jul 10, 2019 5:59 pm
 It would be interesting to see if the issue apears when any powered USB device (such as a simple powered hub) is attached to a Pi 4 before boot.
Same problem when restarting with a powered USB hub that presumably backpowers the RPi
by trejan
Wed Jul 10, 2019 5:02 pm
Forum: General discussion
Topic: Pi4b J2 Run Global_En as power
Replies: 6
Views: 1958

Re: Pi4b J2 Run Global_En as power

RUN is for resetting the SoC. GLOBAL_EN is for signalling the PMIC to leave the low power shutdown state. Neither should be used for powering a fan.
by trejan
Wed Jul 10, 2019 3:33 pm
Forum: General discussion
Topic: POE Junper
Replies: 3
Views: 367

Re: POE Junper

No. Those pins connect to the ethernet magnetics so the PoE HAT can draw power from them. It doesn't have 5V on there.

The RPi schematics show how those 4 pins are wired.
by trejan
Wed Jul 10, 2019 11:31 am
Forum: General discussion
Topic: 3v3 drops on Pi4 reboot
Replies: 5
Views: 864

Re: 3v3 drops on Pi4 reboot

Technocolour wrote: ↑
Tue Jul 09, 2019 5:06 pm
 That got me curious for what kind of caps one would need to buffer it, so I measured it with my Rigol scope, and it goes dark for just shy of 60ms.
Doesn't sound like a good idea to do that from this post. The PMIC won't startup if it sees 3.3V.
by trejan
Wed Jul 10, 2019 11:27 am
Forum: Troubleshooting
Topic: Raspberry Pi 4 reboot fails when a powered usb hub is attached
Replies: 16
Views: 4921

Re: Raspberry Pi 4 reboot fails when a powered usb hub is attached

Yeah. Don't backpower the RPi 4 via the USB socket.
by trejan
Tue Jul 09, 2019 11:31 pm
Forum: General discussion
Topic: PWM pins on the Pi 4
Replies: 6
Views: 8284

Re: PWM pins on the Pi 4

Since the Pi 4 uses a different processor, is it possible to use the audio jack and still have at least 1 PWM-able pin free to program on now? Yes. The headphone socket has its own separate PWM peripheral now. You can use PWM0 and PWM1 on the expansion header without interfering with the analog aud...
by trejan
Tue Jul 09, 2019 10:21 pm
Forum: General discussion
Topic: Reasoning behind dual Micro HDMI, and potential future alternatives?
Replies: 125
Views: 13682

Re: Reasoning behind dual Micro HDMI, and potential future alternatives?

As I understand it, the recent version of DP is compatible with HDMI 2.0. And--funnily enough--the Pi4B output is HDMI 2.0. If you're talking about DP++ then that is only for DP sources. A DP++ source has the ability of reconfiguring itself to output a HDMI signal. A DP sink on a monitor still can'...
by trejan
Tue Jul 09, 2019 9:52 pm
Forum: Troubleshooting
Topic: Pi 4 fails to boot when active USB switch attached
Replies: 16
Views: 4356

Re: Pi 4 fails to boot when active USB switch attached

Another way of avoiding the issue may be to insert a diode in the red power wire in the USB cable between the switch and the PI, so that the switch can be powered from the Pi but the Pi can't be back-powered from the "other computer" via the switch. I'd be wary of the voltage drop on that even with...
by trejan
Tue Jul 09, 2019 6:49 pm
Forum: Beginners
Topic: Pi 3 B Raspbian Buster problems
Replies: 3
Views: 1931

Re: Pi 3 B Raspbian Buster problems

Captain-Pie wrote: ↑
Tue Jul 09, 2019 6:35 pm
 During it’s very 1st boot, below the raspberry logos I got this:
[0.235535] cma: cma_alloc: alloc falled,req-size:2025 pages, ret: -12
You can ignore this error. It is harmless.
by trejan
Tue Jul 09, 2019 6:12 pm
Forum: Beginners
Topic: Pi3B+ Power connector
Replies: 7
Views: 393

Re: Pi3B+ Power connector

Oddly I now get an "undervoltage detected " lightning symbol although the board continues to work. This was never a problem before. I'm not sure if this is a result of my soldering or simply comes with the territory when connecting power in this way. You bypass the polyfuse on the power input of th...
by trejan
Tue Jul 09, 2019 4:30 pm
Forum: Troubleshooting
Topic: Right way to fsck/repair root partition
Replies: 5
Views: 2883

Re: Right way to fsck/repair root partition

tmo0 wrote: ↑
Tue Jul 09, 2019 4:28 pm
 And "fsck.mode=force" is not documented (or at least i cant find it) so its risky to add to cmdline.txt.
Documented here.
by trejan
Tue Jul 09, 2019 4:20 pm
Forum: General discussion
Topic: cannot install docker on raspbian buster
Replies: 4
Views: 2034

Re: cannot install docker on raspbian buster

The Docker install script hasn't been updated for Buster yet. Supposedly the Stretch install does work if you edit the script.
by trejan
Tue Jul 09, 2019 1:16 pm
Forum: Troubleshooting
Topic: delete files without permission
Replies: 3
Views: 297

Re: delete files without permission

The ability to delete a file is whether you have write access to the directory the file is in. It isn't the permissions or ownership of the file itself. This is just how permissions work in UNIX so it isn't specific to Raspbian or the RPi. If you don't want people deleting or modifying specific file...
by trejan
Tue Jul 09, 2019 2:42 am
Forum: General discussion
Topic: Accessing GPIO connector with Flirc case
Replies: 2
Views: 537

Re: Accessing GPIO connector with Flirc case

If I were to use a Flirc case how hard would it be to connect/disconnect the 40-pin ribbon cable as needed? There is a slot on the plastic bottom plate. You'll need to completely disassemble the case to get the connector on/off though. Look at the photos by karrika . The gen 1, gen 2 and RPi 4 case...
by trejan
Tue Jul 09, 2019 1:18 am
Forum: Advanced users
Topic: Can a PI be added to a 8bit game cartridge?
Replies: 9
Views: 545

Re: Can a PI be added to a 8bit game cartridge?

I didn't mean it was the same setup but it does have similar requirements of interfacing the RPi GPIOs to a 5V cartridge bus. It isn't trivial to do and requires quite a lot of adjustment to get working right. You can throw more hardware at the problem to make it easier though. Making a bridge using...
by trejan
Tue Jul 09, 2019 1:00 am
Forum: General discussion
Topic: Missing Python 3 Idle in the Programming Menu
Replies: 12
Views: 7546

Re: Missing Python 3 Idle in the Programming Menu

It was removed from the default Raspbian image but it is still in the repo. Try running "sudo apt install idle".

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