RPi 5 USB C PD

Most Pi models in the past have never been fully standards compliant on their USB power connector, I doubt the Pi 5 will be either. There are flaws in this area in pretty much every one of their models, it wont change, it's embedded in their corporate culture. To save risk of incompatibility, you may as well bite the bullet and purchase the official Pi power supply which offers up the full 5A. 

Otherwise, its just an expense buying a special cable and a USB-C PD charger that supports that high current, it can be close to $100 for a decent charger and cable. The Pi official charger is cheap in comparison. Granted one may already have a phone charger, but I think if you need the max power, then the only thing that will be supported is that official Pi supply, and all bets are off if any other charger is used. Thats just from experience with the general unreliability of previous Pi models when the official power supply was not used. Also guaranteed each time one has a problem with the Pi, people will ask "are you using the official power supply?".

The Raspberry Pi 5 does not use the newer Programmable Power Supply (PPS) standard with a 5 volt 5 amps profile. (There isn't an official 5 volt, 5 amp profile in USB-PD.)

This is why they are selling a separate power adapter to enable 5 Amps:

www.raspberrypi.com/.../

Great information. 

Is there RPi 5 status information telling what is the status of the USB C PD and cable being used?

Good news the RPi 5 offical power supply showed up in the mail.  I have been using a 5V 4A power supply with only USB keyboad and mouse.  The USB ports total current is limited to 600 MA.  With the RPi 5 offical power supply this limit is incresed to 1.6 M. Therefore, the RPi 5 does know the capability of the USB C PD being used. Where would this information be found in the RPi 5?

WA9ONY said:

Where would this information be found in the RPi 5?

That is a very good question...

If there is, it may be documented in blogs, YouTube videos, etc. eventually, as users explore the code and the hardware, under a microscope (some even X-ray it!).

They rely on the community of users for support and documentation mostly, because it saves them millions of $ per year (their words, not mine). Unless there's better documentation, USB-PD monitor tools can be used to see what voltage and current are being supplied (this will work with all USB-C devices). They cost around $30 USD. I use this one, it's not bad (I didn't spend a lot of time researching it when I bought it, so there may be much better ones for the price too, but it seems to work fine):

But, as mentioned, I don't think it's worth the effort to use a USB charger for reliability reasons (at least with earlier Pi models, the official power supplies didn't supply 5.0V, they were designed to supply a voltage right at the edge of the tolerance). Who knows what unusual stuff they've had to do with the Pi 5 official supply : (

Personally, I'm not planning to use the Pi 5 for at least 6 months or so, until others have discovered issues or tricks/tips. Especially if the Pi 5 is required for additional hardware (the drivers will have differences for a lot of add-ons). I think the best advice is to use a known working Pi 3 or Pi 4, and only use a Pi 5 if it's necessary because it is fairly well established by now how to power the Pi 3 and Pi 4 if official power supplies are not used.

Even between Pi 3 and Pi 4, there is some hardware that won't work on Pi 4 but will work with Pi 3, because drivers are different between those models too.

One would need to record and decode the messages that are sent over the CC line. There must be a very non-standard profile being sent by the official RPi power supply. Alternatively they might be using vendor defined messages, which are part of the PD communication messages spec.

When I have my equipment back and get my hands on RPi5 equipment, I would love to go down that rabbit hole.

Or they may have taken the lazy approach, and simply allow the power lines to draw 5A regardless of the limit that would be associated with the negotiation! : ) 

i.e. I'm wondering if their AC-DC converter simply is not monitored at 3A, since it's just a sense-resistor change to make their chip think it's within spec.

Yeah, I am sure it does not limit the current. But still the RPi5 needs to know that it is connected to an official PS, to allow 1.6A for the USB ports as WA9ONY describes.

I had an early (before e-marker cables) 95W power supply, it was happily supplying 5A at any voltage. Was great for testing trigger boards.

Ah, good point. I had forgotten about that.

I tore apart a Microsoft laptop power supply brick the other day, and they were monitoring current using an INA213 chip, which was neat. But that was a £100 power supply.