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<DC-IRC> <Tonymac32> yep
<DC-IRC> <clever___> i have found parts of the PD protocol on the pi5, and it even has checks for the usb VID of the official pi PSU
<DC-IRC> <clever___> and since its mostly in software, they can always patch it to fix compatibility bugs
<DC-IRC> <clever___> assuming its nothing severe, like the PSU turning power off for 2 seconds when enabling 5a mode
<DC-IRC> <Tonymac32> I'm not even saying there will be a fault on the side of the Pi
<DC-IRC> <Tonymac32> if you don't want to risk a fire it's going to have a million reasons to limit current
<DC-IRC> <clever___> yeah
<DC-IRC> <Tonymac32> so "limp mode" is going to be a constant issue for users' complaints
<DC-IRC> <Tonymac32> for transparency I made fun of everyone else's 5V boards too, clear back to the Asus Tinker Board in 2017
<DC-IRC> <clever___> related, there is a new safety in the pi5 firmware, if you try to boot from usb, and the PSU isnt able to supply enough amps, it will pause booting, display a warning on the hdmi, and blink 1 long 1 short
<DC-IRC> <Tonymac32> interesting
<DC-IRC> <clever___> you can then accept the risks, and click the power button once to continue booting
<DC-IRC> <clever___> or set a config flag to always accept it
<DC-IRC> <clever___> i can see that happening for a dumb supply, like a 5v5a bench PSU into the gpio header
<DC-IRC> <clever___> it has no way to ask the current limit
<DC-IRC> <Tonymac32> *remembers this is the perpetual lightning bolt community*
<DC-IRC> <Tonymac32> 🙂
<DC-IRC> <clever___> and now it wont even boot, until you are told the risks
<DC-IRC> <Tonymac32> That's a decent mitigation, but they should have just built it properly in the first place
<DC-IRC> <clever___> i'm also not sure, if its using the usb descriptors, or just any usb
<DC-IRC> <clever___> and there is the problem that usb descriptors often lie
<DC-IRC> <clever___> `Bus 001 Device 120: ID 1b1c:1b81 Corsair CORSAIR DARK CORE RGB PRO Gaming Dongle`
<DC-IRC> <clever___> for example, i have this dongle for my mouse
<DC-IRC> <clever___> the usb descriptor claims it only needs 100mA
<DC-IRC> <clever___> `[Tue Oct 17 00:12:44 2023] usb 1-11.1.2: Not enough bandwidth for new device state.`
<DC-IRC> <clever___> ah, mis-remembered
<DC-IRC> <clever___> the usb hub in my keyboard cant support it, but because of bandwidth, not mA
<DC-IRC> <clever___> ah, i see why, my keyboard only has a full-speed hub!, 12mbit!!
<DC-IRC> <Tonymac32> nice
<DC-IRC> <clever___> but i have heard about devices lying about the total power usage, because hosts are lax on current limiting, and users never use a powered hub
<DC-IRC> <Tonymac32> 600 mA shared to all 4? eek
<DC-IRC> <clever___> yeah
<DC-IRC> <Tonymac32> and 1.6A isn't even really "good", but at least it shouldn't roll over and die
<DC-IRC> <Tonymac32> 900 mA each for the blue ports per spec is over
<DC-IRC> <Tonymac32> (not that most vendors in this space design around USB appropriately)
<DC-IRC> <Tonymac32> I ran 4 spinning disks off of a Tinker Board 2 and was overjoyed 😄 😄 now if only they did any software support...
<DC-IRC> <Tonymac32> they moved the PoE header... 🤦‍♂️
<DC-IRC> <clever___> and the whole ethernet port
<DC-IRC> <clever___> they claim its because of pcb routing issues, and the pinout of the new RP1
<DC-IRC> <Tonymac32> eh that flip flops because they're bored I guess
<DC-IRC> <Tonymac32> mangling a HAT interface though
<DC-IRC> <clever___> the poe always has to be beside the ethernet
<DC-IRC> <Tonymac32> the RP1 is their chip, change the pinout 😛
<DC-IRC> <clever___> since its just the center-tap of the 4 coils
<DC-IRC> <Tonymac32> you can run it on traces like any other power
<DC-IRC> <clever___> and then you have high current AC running across data lines?
<DC-IRC> <Tonymac32> I guess they really did use some really low layer count
<DC-IRC> <Tonymac32> sheesh
<DC-IRC> <clever___> and the magnetic field from it, could induce currents in other signals
<DC-IRC> <Tonymac32> since when did they care about that? flash photography, wifi and hdmi, etc etc etc
<DC-IRC> <Tonymac32> seems like more reason for them to do it
<DC-IRC> <clever___> heh
<DC-IRC> <Tonymac32> And yeah, they did it before:
<DC-IRC> <clever___> ah, interesting
<DC-IRC> <clever___> another thing to keep in mind, is the rgmii
<DC-IRC> <Tonymac32> I have a small pile of form-factor clones that do it to, I thought PoE was DC
<DC-IRC> <clever___> i think PoE is 4 phase AC, using each diff-pair in the ethernet, as a single phase
<DC-IRC> <Tonymac32> Anyway, just irritating if you stockpile hardware to have to retool
<DC-IRC> <clever___> so there is a dc offset applied to the whole differential pair, relative to itself
<DC-IRC> <clever___> but AC overall, relative to other pairs
<DC-IRC> <Tonymac32> hmmm but that wouldn't make it through the filters I've seen
<DC-IRC> <clever___> then you just have a 4 phase full-bridge rectifier, to get dc out the other end
<DC-IRC> <clever___> but maybe i'm mis-remembering, and that rectifier is only for crossover reasons?
<DC-IRC> <clever___> passive and active poe are different things, much like passive and active usb-pd
<DC-IRC> <Tonymac32> of course
<DC-IRC> <Tonymac32> unfortunately I've only been messing with power over single-pair ethernet recently
<DC-IRC> <Tonymac32> automotive doesn't usually go higher
<DC-IRC> <Tonymac32> it's an interesting space for competing with CAN anyhow
<DC-IRC> <clever___> ive heard that active poe, communicates with the source, by drawing varying amounts of current, in a set pattern
<DC-IRC> <clever___> and if you dont follow that pattern correctly, it heavily limits the current
<DC-IRC> <Tonymac32> goes into the chips and piece parts
<DC-IRC> <clever___> > The switch can supply power to either set of pairs, or even both at the same time. The bridge rectifiers ensure that polarity is correct, in case someone uses a crossover cable.
<DC-IRC> <clever___> ah, i was remembering wrong on what the rectifiers did
<DC-IRC> <clever___> @mackahan https://www.youtube.com/watch?v=vc8xWyJuQY0