![]() ![]() ![]() The main culprit here is the MPS MP8007 PoE power IC (PDF link), with its relatively sluggish flyback DC-DC converter implementation being run at 100 kHz (recommended <200 kHz in datasheet). It essentially rendered the USB ports unusable due to over-current protection kicking in. While the Raspberry Pi 2’s issue was indeed hard to predict and objectively more adorable than dangerous, the issue with the Power over Ethernet (PoE) HAT was decidedly less cute. The fix for this is to cover the chip in question with an opaque material before doing something like taking any photos of it with a xenon flash, or pointing a laser pointer at it. The resulting disruption led to the chip’s regulation safeties kicking in and shut the entire system down, fortunately without any permanent damage. In this case some electromagnetic radiation - like the light from a xenon camera flash - enter the die, causing a photoelectric effect. ![]() Unfortunately, as is the risk with any wafer-level packaging like this, it exposes the bare die to the outside world. In brief, the Raspberry Pi 2 single-board computer (SBC) employs a wafer-level package ( WL-CSP) that performs switching mode supply functionality. Join me below for a brief recap of those previous issues, and an in-depth summary of USB-C, the differences between regular and electronically marked (e-marked) cables, and why detection logic might be making your brand-new Raspberry Pi 4 look like an analogue set of headphones to the power delivery hardware.Ī Trip Down Memory Lane The Raspberry Pi 2, with the camera shy U16 IC in the lower left.īack in February of 2015, a blog post on the official Raspberry Pi blog covered what they figured might be ‘ the most adorable bug ever‘. It would be fair to say that the Raspberry Pi team hasn’t been without its share of hardware issues, with the Raspberry Pi 2 being camera shy, the Raspberry Pi PoE HAT suffering from a rather embarrassing USB power issue, and now the all-new Raspberry Pi 4 is the first to have USB-C power delivery, but it doesn’t do USB-C very well unless you go for a ‘dumb’ cable. ![]()
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