Ancestors

Written by Manawyrm | Sarah on 2024-09-01 at 21:22

New blog post:

Executing Linux applications on a Raspberry Pi in less than 3.5s from power-up! 🚀🏎️

(and other power saving tricks)

https://kittenlabs.de/blog/2024/09/01/extreme-pi-boot-optimization/

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Written by Graham Sutherland / Polynomial on 2024-09-01 at 22:49

@manawyrm something worth trying is dropping the 5V supply voltage for the Pi down to 4V. the limited schematics available show the board using PAM2306 and RT8088 buck regulators to derive the 3.3V and VDD_CORE voltage rails. the PAM2306 goes from 60% efficient at 5V up to 85% efficient at 4V in, which is a major increase. the RT8088 gains a couple of percent efficiency by dropping to 4V too.

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Written by Manawyrm | Sarah on 2024-09-01 at 22:52

@gsuberland Uhhh! Interesting! That should be easy to test, thanks.

Not sure what the camera module thinks of this, but I‘ll give it a shot!

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Written by Graham Sutherland / Polynomial on 2024-09-01 at 22:53

@manawyrm according to the schematic I'm looking at, the camera port runs 3.3V, so you'll be saving power there too.

https://datasheets.raspberrypi.com/rpizero2/raspberry-pi-zero-2-w-reduced-schematics.pdf

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Written by Manawyrm | Sarah on 2024-09-01 at 22:53

@gsuberland Huh!! Thanks 😻

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Written by Graham Sutherland / Polynomial on 2024-09-01 at 22:56

@manawyrm I don't know where else the 5V rails go on the board since I don't have the rest of the schematic, but based on how they've named the power nets it's a pretty reasonable guess that the only other usage of the 5V rail is for the USB ports, and since you're disabling those anyway you should be fine. the 5V_CORE is almost certainly a filtered power domain used only for the RT8088.

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Written by Timon 🛠 on 2024-09-01 at 23:01

Yea, like 99% certain 5V only powers the regulators and the USB ports.

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Toot

Written by Timon 🛠 on 2024-09-01 at 23:04

Ah its a zero, yea then def. nothing critical. On Pi5 I'm not as certain with RP1.

HDMI also needs the 5V for the EDID but that will be fine at 4V too.

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Descendants

Written by Graham Sutherland / Polynomial on 2024-09-01 at 23:09

@timonsku EDID is also disabled here so it sounds like we're golden

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