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by jdb
Tue Jun 25, 2019 5:16 pm
Forum: General discussion
Topic: Raspberry Pi 4 Thread - general discussion
Replies: 424
Views: 21009

Re: Raspberry Pi 4 Thread - general discussion

There is a feature of the Pi4 SoC that I'm surprised hasn't had more (any?) comment. That is that the Ethernet connection no longer runs through the USB hub. This means that a USB-attached SSD and the network connection won't be fighting over bandwidth. That alone should make a significant performa...
by jdb
Tue Jun 25, 2019 9:35 am
Forum: Troubleshooting
Topic: Raspberry Pi 4 temperature
Replies: 12
Views: 557

Re: Raspberry Pi 4 temperature

- Please post the contents of config.txt
- What is the output of "vcgencmd measure_volts"?
- What display(s) do you have plugged in?
by jdb
Mon Jun 24, 2019 7:58 pm
Forum: General discussion
Topic: Raspberry Pi 4 Thread - general discussion
Replies: 424
Views: 21009

Re: Raspberry Pi 4 Thread - general discussion

Has the maximum number of USB endpoints been increased? It would be good to be able to hook up more than half a dozen USB peripherals. It's an xHCI controller - number of endpoints is no longer the limit, number of device slots is. HCSPARAMS1 = 0x05000420 -> 0x20 for number of slot IDs -> 32 simult...
by jdb
Mon Jun 24, 2019 2:51 pm
Forum: General discussion
Topic: Raspberry Pi 4 - Sleep Mode
Replies: 7
Views: 654

Re: Raspberry Pi 4 - Sleep Mode

"sudo poweroff" will shut down the PMIC at the conclusion of the shutdown sequence. This reduces power consumption to about 3mA but requires pulling GLOBAL_EN low (or cycling input power) to wake the PMIC up. There's user-modifiable EEPROM setting to change this behaviour (halt instead of poweroff, ...
by jdb
Mon Jun 24, 2019 12:00 pm
Forum: Advanced users
Topic: Does the Raspberry Pi 4 officially support micro-SD cards with more than 32GB?
Replies: 3
Views: 338

Re: Does the Raspberry Pi 4 officially support micro-SD cards with more than 32GB?

Using our recommended software imaging tools, there was never a constraint on the size of SD card used.

Pi 4's boot partition must be fat32 or fat16, as is the case with previous models.
by jdb
Mon Jun 24, 2019 10:54 am
Forum: General discussion
Topic: Raspberry Pi 4 Thread - general discussion
Replies: 424
Views: 21009

Re: Raspberry Pi 4 Thread - general discussion

Audio jack is still PWM driven, but there are now two PWM controllers with one dedicated to audio.

The new SD controller is an addition, not a replacement. The Broadcom SDHOST device is now unused as the Arasan SD controller now talks to WiFi.
by jdb
Mon Jun 24, 2019 10:50 am
Forum: General discussion
Topic: Raspberry Pi 4 Thread - general discussion
Replies: 424
Views: 21009

Re: Raspberry Pi 4 Thread - general discussion

smed wrote:
Mon Jun 24, 2019 10:49 am
Any chance it supports DisplayPort over USB-C?
No, USB2.0 OTG only.
by jdb
Mon Jun 24, 2019 10:24 am
Forum: General discussion
Topic: Raspberry Pi 4 Thread - general discussion
Replies: 424
Views: 21009

Re: Raspberry Pi 4 Thread - general discussion

Is the _analog_ audio still the same, level, impedance etc.? With the Pi3 and the new driver, audio quality is acceptable, but it is difficult to use decent headphones without overloading the output or ending up with very low volume. Unchanged. The recommendation is to use 32 ohm impedance headphon...
by jdb
Mon Jun 24, 2019 10:10 am
Forum: General discussion
Topic: Raspberry Pi 4 Thread - general discussion
Replies: 424
Views: 21009

Re: Raspberry Pi 4 Thread - general discussion

The new hardware seems pretty much what people have been asking for. A few questions: 1. Are all the USB ports behind an internal HUB or can some of them function in gadget mode? 2. Will Mathematica still run? 3. Is there a list of compatible hats? For example, does the unicorn hat still work? Than...
by jdb
Mon Jun 24, 2019 10:00 am
Forum: General discussion
Topic: Raspberry Pi 4 Thread - general discussion
Replies: 424
Views: 21009

Re: Raspberry Pi 4 Thread - general discussion

Killertechno wrote:
Mon Jun 24, 2019 9:58 am
Are you planning to build CM4 and/or any upgrade for CM3?
CM4 will exist at some point - but there are significant challenges to making all the gubbins fit in an SODIMM footprint.
by jdb
Mon Jun 24, 2019 9:50 am
Forum: General discussion
Topic: Raspberry Pi 4 Thread - general discussion
Replies: 424
Views: 21009

Re: Raspberry Pi 4 Thread - general discussion

Under the skin, much is different. This is the biggest HW change in Pi history. Exciting. I guess there will be some general-audience blog posts or articles going into the details when the time is right. Can I ask if HDMI sound would be able to play independently via each HDMI port? As of right now...
by jdb
Mon Jun 24, 2019 9:09 am
Forum: General discussion
Topic: Raspberry Pi 4 Thread - general discussion
Replies: 424
Views: 21009

Re: Raspberry Pi 4 Thread - general discussion

Also, perhaps you should have read the documentation on the new peripheral alt settings: https://www.raspberrypi.org/documentati ... minary.pdf Is there any register documentation yet for all these nice new i2c, uarts etc? They are going to be real handy especially for those big robotics projects. ...
by jdb
Mon Jun 24, 2019 8:57 am
Forum: General discussion
Topic: Raspberry Pi 4 Thread - general discussion
Replies: 424
Views: 21009

Re: Raspberry Pi 4 Thread - general discussion

Thank you! !! Debian Buster for the Pi 4 is it 64bit ? Is it possible to use the Pi 4 as usb OTG ? I need to emulate USB stick. Buster will release with a 32-bit userland, as backwards compatibility for all previous models is important. The Pi 4 kernel uses LPAE but eventually we'll ship a 64-bit k...
by jdb
Mon Jun 24, 2019 8:50 am
Forum: General discussion
Topic: Raspberry Pi 4 Thread - general discussion
Replies: 424
Views: 21009

Re: Raspberry Pi 4 Thread - general discussion

The VC4 VPU is still there (and boots first). Bootcode.bin has moved to an on-board EEPROM so when we release Ethernet/USB mass-storage bootmodes, it'll be a bootloader upgrade and not a bootrom (new chip) upgrade. I see thanks. So I guess VPU still sets up the memory at startup then. How did you s...
by jdb
Mon Jun 24, 2019 8:39 am
Forum: General discussion
Topic: Raspberry Pi 4 Thread - general discussion
Replies: 424
Views: 21009

Re: Raspberry Pi 4 Thread - general discussion

tevey wrote:
Mon Jun 24, 2019 8:37 am
Seems to be conflicting information out there.
Can it run 2x4k at the same time, or can it only run 1x4k or 2x1080p?
2x4Kp30, 1x4Kp60.
Dual 1440p60 also works.
by jdb
Mon Jun 24, 2019 8:38 am
Forum: General discussion
Topic: Raspberry Pi 4 Thread - general discussion
Replies: 424
Views: 21009

Re: Raspberry Pi 4 Thread - general discussion

complete nonsense that 3A power supply thing via USB-C! They must finally install a power jack like Arduinos for standard 7-12V power adapters! In addition, there is always a missing button to start and stop! I also do not understand why they stick to their puny form factor and not finally grow for...
by jdb
Mon Jun 24, 2019 8:08 am
Forum: General discussion
Topic: Raspberry Pi 4 Thread - general discussion
Replies: 424
Views: 21009

Re: Raspberry Pi 4 Thread - general discussion

Before the complaints come in, that's a preliminary datasheet, a much more detailed ones is on its way. Yes, It will be nice to know more about the CPU, I cannot find the CPU model number. The document says the system will prevent SOC's temperature go above 85C degree, but when will it start thrott...
by jdb
Mon Jun 24, 2019 6:57 am
Forum: General discussion
Topic: Raspberry Pi 4 Thread - general discussion
Replies: 424
Views: 21009

Re: Raspberry Pi 4 Thread - general discussion

DarkPlatinum wrote:
Mon Jun 24, 2019 6:56 am
I might be asking too much, but does the micro SD card slot have the same data transfer speed as before?
No. Double.
DDR50 is now supported and the controller now supports ADMA.
by jdb
Fri Jun 21, 2019 3:37 pm
Forum: Compute Module
Topic: USB 2.0 Dropped frames
Replies: 14
Views: 1093

Re: USB 2.0 Dropped frames

As long as there are some host channels free, they get rotated between endpoints in a roughly round-robin fashion. The killers are USB bulk-IN endpoints that never return data - for example, GSM modems that are idle. These also typically have multiple bulk endpoints which compounds the problem. The ...
by jdb
Fri Jun 21, 2019 3:10 pm
Forum: General discussion
Topic: Is my HDMI port fried? RPi 3B+
Replies: 14
Views: 669

Re: Is my HDMI port fried? RPi 3B+

@OP you need to get your electrics checked.

If you squish a power cord and it takes out other equipment in your house then there is something seriously wrong with your earthing or circuit protection. A semi-fried Pi HDMI port is the least of your worries.
by jdb
Thu Jun 13, 2019 1:00 pm
Forum: Compute Module
Topic: USB 2.0 Dropped frames
Replies: 14
Views: 1093

Re: USB 2.0 Dropped frames

Noted about I2S - while the peripheral can be driven in slave mode (from an external clock), and can be driven at high bitrates, the required rate is likely too fast for most other I2S interfaces. There is a possibility that I can slightly mangle isochronous scheduling. For a sequence of isochronous...
by jdb
Tue Jun 11, 2019 4:06 pm
Forum: Compute Module
Topic: USB 2.0 Dropped frames
Replies: 14
Views: 1093

Re: USB 2.0 Dropped frames

The USB hardware supports DMA transfers at the granularity of a single USB transfer. There is no support for chaining transfers together, so each USB transfer results in a interrupt to the CPU which must be handled by software. The only exception to this is high-speed bulk, where the core can transf...
by jdb
Tue Jun 11, 2019 1:23 pm
Forum: Compute Module
Topic: USB 2.0 Dropped frames
Replies: 14
Views: 1093

Re: USB 2.0 Dropped frames

USB2.0 isochronous suffers from a subset of the issues that beset full-speed isochronous split transactions. Typically USB1.1 isochronous transfers are scheduled every full-speed frame and must complete within that frame or the hub will drop the transfer (or response data). This means that the host ...
by jdb
Fri May 31, 2019 10:17 am
Forum: General discussion
Topic: RISC-V
Replies: 135
Views: 8095

Re: RISC-V

Not just a memory controller - you need a SDRAM PHY of substantial complexity to talk to anything more complicated than PC133 SDRAM - DDR2 and onwards needs complicated lane deskew and impedance compensation. This part of the interface ends up being almost pure analogue logic and so far the "open so...
by jdb
Fri May 31, 2019 9:38 am
Forum: General discussion
Topic: Is there a way to reset the status returned by vcgencmd get_throttled?
Replies: 10
Views: 297

Re: Is there a way to reset the status returned by vcgencmd get_throttled?

Actually, the argument passed to get_throttled changes the variable returned, and acts as a bitmask to reset the additional variable. There are two sets of sticky bits, permanent and recent. a) get_throttled with no arguments returns permanent sticky bits in the top 16 bits - these are never reset. ...

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