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by jdb
Sat Apr 21, 2018 11:42 am
Forum: Troubleshooting
Topic: Raspberry Pi 3 B+ lockups
Replies: 209
Views: 7438

Re: Raspberry Pi 3 B+ lockups

Definitely the SoC and not the RAM? When we do qualification testing of a new piece of silicon, we make boards with split lots on. These are special SoCs that have been "skewed" in the semiconductor manufacturing process to emulate the maximum differences in performance/speed/power that you would g...
by jdb
Fri Apr 13, 2018 8:42 am
Forum: Advanced users
Topic: Raspberry Pi 3b+ and I2C to MXL7704 PMIC
Replies: 4
Views: 313

Re: Raspberry Pi 3b+ and I2C to MXL7704 PMIC

The VC4 firmware will periodically read from the PMIC in order to poll for the undervoltage flag. If you did try bitbashing the relevant GPIOs (the PMIC is not connected to any pins that map to the I2C peripheral) then the firmware would trample on your communication and you'd get nothing but nonsen...
by jdb
Fri Apr 06, 2018 3:56 pm
Forum: General discussion
Topic: New Raspberry Pi model 3B+ 1.4 GHz, 330Mbit Ethernet, 802.11ac, PoE
Replies: 387
Views: 24383

Re: New Raspberry Pi model 3B+ 1.4 GHz, 330Mbit Ethernet, 802.11ac, PoE

Unstickying as we are now 3 weeks post-launch.
by jdb
Thu Apr 05, 2018 9:33 pm
Forum: General discussion
Topic: RPi 3B+ gigabit ethernet bad download speeds.
Replies: 146
Views: 7740

Re: RPi 3B+ gigabit ethernet bad download speeds.

resiakt (tkaiser), In all honesty, your posts are becoming childishly tiresome and pointless. What good information you are adding to the thread is being outweighed by your obsession over nonexistent censorship. Please, give it a rest... -Robert This resiakt was yet another sockpuppet account, ther...
by jdb
Thu Apr 05, 2018 9:49 am
Forum: General discussion
Topic: First Post: What's the hole for in the Broadcom BCM2837B0 heat spreader?
Replies: 5
Views: 696

Re: First Post: What's the hole for in the Broadcom BCM2837B0 heat spreader?

that "hole" indicates where ball a1 or pin 1 is. If it was required just for orientation, then it would be laser etched and not a hole. The hole is there to allow for venting when the SoC is being soldered on to the board. The thermal epoxy between the die and heatspreader may off-gas at 200C so a ...
by jdb
Wed Mar 28, 2018 8:52 pm
Forum: General discussion
Topic: RPi 3B+ gigabit ethernet bad download speeds.
Replies: 146
Views: 7740

Re: RPi 3B+ gigabit ethernet bad download speeds.

Wasn't me doing the banning this time... It was me. Said poster annoyed me sufficiently to motivate me to wield the banhammer with aplomb, so it was thusly wielded. Pro tip: even if you post technically useful information or analysis on our forums, if you act like you would be kicked out of a house...
by jdb
Tue Mar 20, 2018 12:42 pm
Forum: Advanced users
Topic: Analogue audio redux
Replies: 47
Views: 8131

Re: Analogue audio redux

Yes. Latest Raspbian enables this driver by default.
by jdb
Tue Mar 20, 2018 12:26 pm
Forum: Troubleshooting
Topic: 3V3 Power Rail and GPIO Reading 5.2V
Replies: 10
Views: 473

Re: 3V3 Power Rail and GPIO Reading 5.2V

As a final test, what are the switching nodes on the PAM2306 doing?

Measure the trace going between the switcher and the two SMT inductors with an oscilloscope - you should see switching at about ~1.7MHz.
by jdb
Tue Mar 20, 2018 12:21 pm
Forum: General discussion
Topic: New Raspberry Pi model 3B+ 1.4 GHz, 330Mbit Ethernet, 802.11ac, PoE
Replies: 387
Views: 24383

Re: New Raspberry Pi model 3B+ 1.4 GHz, 330Mbit Ethernet, 802.11ac, PoE

The silicon was mirrored and the top metal layers of the wafer were altered slightly. Bond pads (where wires would have connected) are turned into "bumps" that solder on to the chip substrate - the interposer that goes between the silicon and the PCB underneath. The top metal layers were modified to...
by jdb
Tue Mar 20, 2018 11:16 am
Forum: Troubleshooting
Topic: Stock Pi 3 B+ in chilly UK Temperature Icon :(
Replies: 12
Views: 544

Re: Stock Pi 3 B+ in chilly UK Temperature Icon :(

My 3B+ has settled at 62.3C running your "yes" stress test (in the UK with snow outside). It does have a small heat sink. Try this, it uses NEON ..... wget https://raw.githubusercontent.com/ssvb/cpuburn-arm/master/cpuburn-a53.S gcc -o cpuburn-a53 cpuburn-a53.S ./cpuburn-a53 CPUburn is a pathologica...
by jdb
Tue Mar 20, 2018 11:12 am
Forum: Advanced users
Topic: Analogue audio redux
Replies: 47
Views: 8131

Re: Analogue audio redux

The buffer driving the audio is the same on all models of Pi since B+. The original Model B/A used a noisier arrangement and Zero doesn't have analogue audio output circuitry.
by jdb
Tue Mar 20, 2018 8:56 am
Forum: General discussion
Topic: 64-bit operating system
Replies: 76
Views: 3155

Re: 64-bit operating system

Ok, so "database engines that memory map inordinately huge database files" is one valid reason. Any more? The advantage of 64-bit mode is not only 64-bit memory addresses, but also 64-bit integers in general. Any compute-bound program that makes heavy use of 64-bit integers will show significantly ...
by jdb
Mon Mar 19, 2018 10:45 pm
Forum: General discussion
Topic: 64-bit operating system
Replies: 76
Views: 3155

Re: 64-bit operating system

It is not. There are some odd things that need a 64 bit address space. I believe MongoDB is one. If your database is bigger than 2GB. CockroachDB can get by with 32 bits but needs tweaking to do so. Of course nobody in their right mind is going to be using a Pi for huge databases. Except for experi...
by jdb
Mon Mar 19, 2018 9:22 pm
Forum: General discussion
Topic: 64-bit operating system
Replies: 76
Views: 3155

Re: 64-bit operating system

When will Raspberry Pi organization release a 64-bit operating system?! Ideally the Raspberry Pi 3 B+ will work faster if a 64-bit operating system were available in Raspbian. The current 32-bit operating system may present a bottleneck. In what way is the current ARMv7 Raspbian bottlenecked or lim...
by jdb
Sun Mar 18, 2018 10:38 pm
Forum: General discussion
Topic: Raspberry Pi specs
Replies: 3
Views: 232

Re: Raspberry Pi specs

90ns is way too fast for the CPU to correctly time interrupts or sample GPIOs. You could use the SMI peripheral in "logic analyzer" mode - https://www.raspberrypi.org/forums/viewtopic.php?f=31&t=92233#p1008403 SMI is a generic read-write peripheral that you can use to blast data to/from the GPIOs. I...
by jdb
Thu Mar 15, 2018 10:54 pm
Forum: General discussion
Topic: New Raspberry Pi model 3B+ 1.4 GHz, 330Mbit Ethernet, 802.11ac, PoE
Replies: 387
Views: 24383

Re: New Raspberry Pi model 3B+ 1.4 GHz, 330Mbit Ethernet, 802.11ac, PoE

Does it still have the annoying non-spring-loaded microsd slot? Pity that there is still no wifi connector for external wifi antenna... rf shielding is fun with internal antenna just at side of the chip :) From my tests on rpi3 (and same on rpi2 with wifi adapter connected right on a rpi usb port, ...
by jdb
Thu Mar 15, 2018 9:54 pm
Forum: General discussion
Topic: 3B+ PEN & RUN Header
Replies: 13
Views: 1330

Re: 3B+ PEN & RUN Header

The 3B+ seems to have a change to the RUN header. RUN I assume has the same functionality, in that it's pulled high to allow the Raspberry Pi to run, and pulled low to reset. This comment on the announcement blog page seems to indicate that PEN can be used for shutdown. Will pulling it low put it i...
by jdb
Thu Mar 15, 2018 7:38 pm
Forum: Advanced users
Topic: Moving Linux kernel to 4.14
Replies: 83
Views: 28637

Re: Moving Linux kernel to 4.14

paul433 wrote:
Thu Mar 15, 2018 1:04 pm
Kernel 4.14.21 seemed to be really stable, 4.14.24 we started seeing these kernel panics again. Seems that we have not round the race condition that is causing the problem.
Is the dmesg log/stacktrace any different?
by jdb
Thu Mar 15, 2018 6:18 pm
Forum: Advanced users
Topic: Analogue audio redux
Replies: 47
Views: 8131

Re: Analogue audio redux

This driver is now enabled by default in latest Raspbian.

@trulio I've not had much chance to investigate your bug, but now that 3B+ is out I may have some more time available.
by jdb
Wed Mar 14, 2018 8:23 pm
Forum: General discussion
Topic: New Raspberry Pi model 3B+ 1.4 GHz, 330Mbit Ethernet, 802.11ac, PoE
Replies: 387
Views: 24383

Re: New Raspberry Pi model 3B+ 1.4 GHz, 330Mbit Ethernet, 802.11ac, PoE

it is a shame that they didn't include an option for more RAM like the original Acorn B+. There is an interesting response from Eben on the blog when asked about more memory; "RAM is going through one of its periodic price spikes. It wasn’t feasible to add more to the design while sticking to the $...
by jdb
Wed Mar 14, 2018 6:35 pm
Forum: General discussion
Topic: New Raspberry Pi model 3B+ 1.4 GHz, 330Mbit Ethernet, 802.11ac, PoE
Replies: 387
Views: 24383

Re: New Raspberry Pi model 3B+ 1.4 GHz, 330Mbit Ethernet, 802.11ac, PoE

Let's swap the order of these two statements: I see this as bad design. They knew the PoE headers would require the hat as well, so should have just routed the power leads over. Could have made a tiny hat that may not have interfered with other hats. [...] I'd like to just see the HAT specs and part...
by jdb
Tue Mar 13, 2018 1:56 pm
Forum: Advanced users
Topic: under voltage on the 5V GPIO pins
Replies: 2
Views: 178

Re: under voltage on the 5V GPIO pins

If you have any external circuitry attached to the GPIOs, you should ensure that everything is high-impedance or pulled low to prevent backfeed via the pad ESD diode network. The Pi has undervoltage lockout on all the relevant regulators, but having various uncontrolled currents leaking around the b...
by jdb
Tue Mar 13, 2018 1:44 pm
Forum: Troubleshooting
Topic: [0.416592] bcm2835-aux-uart 20215040.serial : could not get clk: -517
Replies: 2
Views: 124

Re: [0.416592] bcm2835-aux-uart 20215040.serial : could not get clk: -517

The "warning" isn't a warning, it's harmless. -517 is -EAGAIN which means the driver will be re-probed at a later stage in boot (when the clock resource is available).

It only appears on the console when booting as the message priority is incorrectly set. A recent kernel update fixes this.
by jdb
Fri Mar 09, 2018 8:03 pm
Forum: Advanced users
Topic: uFL antenna Pi3 - BT/WiFi question.
Replies: 2
Views: 313

Re: uFL antenna Pi3 - BT/WiFi question.

The unpopulated U.fl pads on the underside of the board were used on pre-production boards for performance testing and characterisation, so yes BT will work. https://www.dorkbotpdx.org/blog/wramsdell/external_antenna_modifications_for_the_raspberry_pi_3 Note that by adding an external antenna, you a...
by jdb
Wed Feb 28, 2018 3:23 pm
Forum: Device Tree
Topic: DT Overlay to force some GPIOs into HiZ from boot
Replies: 25
Views: 1488

Re: DT Overlay to force some GPIOs into HiZ from boot

I was cc'd to the thread by PhilE... Your existing setup using a P-fet is not a recommended configuration. The source-gate resistor will pull the voltage on the GPIO up to 5V which will cause current flow through the ESD structure on the GPIO pad - eventually damaging the pin. Use an open-drain "lev...

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