This week, Jonathan Bennett, Randal Schwartz, and Aaron Newcomb chat about Linux, the challenges with using system modules like the Raspberry Pi, challenges with funding development, and more!
Continue reading “FLOSS Weekly Episode 810: Pi4J – Stable And Boring On The Raspberry Pi”
Last Thursday we were at Electronica, which is billed as the world’s largest electronics trade show, and it probably is! It fills up twenty airplane-hangar-sized halls in Munich, and only takes place every two years.
And what did we see on the wall in the Raspberry Pi department? One of the relatively new AI-enabled cameras running a real-time pose estimation demo, powered by nothing less than a brand-new Raspberry Pi Compute Module 5. And it seemed happy to be running without a heatsink, but we don’t know how much load it was put under – most of the AI processing is done in the camera module.
We haven’t heard anything about the CM5 yet from the Raspberry folks, but we can’t imagine there’s all that much to say except that they’re getting ready to start production soon. If you look really carefully, this CM5 seems to have mouse bites on it that haven’t been ground off, so we’re speculating that this is still a pre-production unit, but feel free to generate wild rumors in the comment section.
The test board looks very similar to the RP4 CM demo board, so we imagine that the footprint hasn’t changed. (Edit: Oh wait, check out the M2 slot on the right-hand side!)
The CM4 was a real change for the compute module series, coming with a brand-new pinout that enabled them to break out more PCIe lanes. Despite the special connectors, it wasn’t all that hard to work with if you’re dedicated. So if you need more computing power in that smaller form factor, we’re guessing that you won’t have to wait all that much longer!
Thanks [kuro] for the tip, and for walking around Electronica with me.
As impractical as most overclocking of computers is these days, there is still a lot of fun to be had along the way. Case in point being [Pieter-Jan Plaisier]’s recent liquid nitrogen-aided overclocking of an unsuspecting Raspberry Pi 5 and its BCM2712 SoC. Previous OCing attempts with air cooling by [Pieter] had left things off at a paltry 3 GHz from the default 2.4 GHz, with the power management IC (PMIC) circuitry on the SBC turning out to be the main limiting factor.
The main change here was thus to go for liquid nitrogen (LN2) cooling, with a small chipset LN2 pot to fit on the SBC. Another improvement was the application of a NUMA (non-uniform memory addressing) patch to force the BCM2712’s memory controller to utilize better RAM chip parallelism.
With these changes, the OC could now hit 3.6 GHz, but at 3.7 GHz, the system would always crash. It was time to further investigate the PMIC issues.
The PMIC imposes voltage configuration limitations and turns the system off at high power consumption levels. A solution there was to replace said circuitry with an ElmorLabs AMPLE-X1 power supply and definitively void the SBC’s warranty. This involves removing inductors and removing solder mask to attach the external power wires. Yet even with these changes, the SoC frequency had trouble scaling, which is why an external clock board was used to replace the 54 MHz oscillator on the PCB. Unfortunately, this also failed to improve the final overclock.
We covered the ease of OCing to 3 GHz previously, and no doubt some of us are wondering whether the new SoC stepping may OC better. Regardless, if you want to get a faster small system without jumping through all those hoops, there are definitely better (and cheaper) options. But you do miss out on the fun of refilling the LN2 pot every couple of minutes.
Thanks to [Stephen Walters] for the tip.
This week, Jonathan Bennett and David Ruggles chat with Frank Delporte about Pi4J, the friendly Java libraries for the Raspberry Pi, that expose GPIO, SPI, I2C and other IO interfaces. Why would anyone want to use Java for the Pi? And what’s changed since the project started? Listen to find out!
Continue reading “FLOSS Weekly Episode 809: Pi4J – Stable And Boring On The Raspberry Pi”
With the latest release of Raspberry Pi OS (formerly Raspbian) the end of the X Window System has become reality, completing a years-long transition period. Although this change between display servers is not something which should be readily apparent to the casual user, the change from the client-server-based X11 protocol to the monolithic Wayland protocol has a number of implications. A major change is that with the display server and window manager no longer being separate units, features such as network transparency (e.g. remote X-sessions) are no longer a native feature, but have to be implemented separately by e.g. the Wayland compositor. Continue reading “Raspberry Pi OS’s Wayland Transition Completed With Switch To Labwc”
It’s fairly insignificant in the scheme of things, and there’s no hardware as yet for us to look at, but there it is. Tucked away in a device tree file, the first mention of a Raspberry Pi 500. We take this to mean that the chances of an upgrade to the Pi 400 all-in-one giving it the heart of a Pi 5 are now quite high.
We’ve remarked before that one of the problems facing the Raspberry Pi folks is that a new revision of the regular Pi no longer carries the novelty it might once have done, and certainly in hardware terms (if not necessarily software) it could be said that the competition have very much caught up. It’s in the Compute Module and the wildcard products such as the all-in-one computers that they still shine then, because even after several years of the 400 it’s not really seen an effective competitor.
So we welcome the chance of an all-in-one with a Pi 5 heart, and if we had a wish list for it then it should include that mini PCI-E slot on board for SSDs and other peripherals. Such a machine would we think become a must-have for any space-constrained bench.
Although initially defined as an issue with GPIO inputs when configured with the internal pull-downs enabled, erratum RP2350-E9 has recently been redefined in the datasheet (page 1341) as a case of increased leakage current. As it is now understood since we previously reported, the issue occurs when a GPIO (0 – 47) is configured as input, the input buffer is enabled, and the pad voltage is somewhere between logic LOW and HIGH. In that case leakage current can be as high as 120 µA with IOVDD = 3.3 V. This leakage current is too much for the internal pull-up to overcome, ergo the need for an external pull-down: 8.2 kΩ or less, per the erratum. Disabling the input buffer will stop the leakage current, but reading the input requires re-enabling the buffer.
The upshot of this issue is that for input applications, the internal pull-downs are useless, and since PIO applications cannot toggle pad controls, the input buffer toggling workaround is not an option. ADC usage requires one to clear the GPIO input enable. In general any circuit that relies on floating pins or an internal pull-down resistor will be affected.
Although this should mean that the affected A2 stepping of the RP2350 MCU can still be used for applications where this is not an issue, and external pull-downs can be used as a ‘fix’ at the cost of extra power usage, it makes what should have been a drop-in replacement a troubled chip at best. At this point there have still been no definite statements from Raspberry Pi regarding a new (B0) stepping, leaving RP MCU users with the choice between the less flashy RP2040 and the buggy RP2350 for the foreseeable future.
Header: Thomas Amberg, CC BY-SA 2.0.
