Hello,
I have a short question and I hope you can help:
as I understand it the first release of the Pi 4 had issues with the USB-C port.
Has that been fixed and a new hardware revision is released and if so how can I tell if an online shop is selling the fixed version?
Thanks for your help.
-- SunDancer All your squigs are belongz to me! [TAG] Fairy & [POLL]-Enforcer https://blog.der-boese-metaller.de
This has been fixed for quite some time now. How you can tell? Probably by buying at a shop that sells huge numbers of them. Tomshardware writes
"We reached out to Raspberry Pi CEO Eben Upton to ask how users can tell whether they're purchasing a new revision board or an old model, and he said that the best way to tell is by testing the board with an electronically marked cable to see if it works."
So there probably is no way you can see it from outward appearance.
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On the other hand someone on Amazon.de wrote in an review that in March he got version 1.1 c03111 instead of Revision 1.2 c03112.
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From Tom's Hardware:
The problem had to do with the Pi 4's USB Type-C port, which it uses to receive power. The way that the port was constructed meant that it would not work with high-speed, "e-marked" cables. We tested a wide number of cables to see which would work, but found that most cables did not have any issues.
In short, if you have a USB 3.1 5 or 10 Gbps cable, chances are that it it is "electronically marked" while USB 2.0 cables are just fine. The high-speed cables require two pull down resistors on the Type-C port, because they use two lines to talk to the system. The original Pi 4 had only one resistor so these cables won't work with it. Considering that the Pi 4's USB-C port is only usable for charging, chances are that you wouldn't want to use a high-speed data cable with it anyway.
-- Chris Elvidge, England
What a difference it makes? IMO none as the data part of the cable is not being used
But the Pi and the charger would probably still talk on the data lines when the cable was first inserted, to negotiate the charging voltage and current that was available from the charger and required by the Pi. The negotiation may be slightly different since the PSU is actually supplying the current that the Pi needs to operate, as opposed to charging a battery, so supplied reduced current (with a longer charging time) would not be an option - it's all or nothing.
The USB 2 part of the USB-C socket is used by the Pi - that's where the Pi's USB 2 controller is connected (the same component as provides previous Pis' USB). To use it, you need either a powered hub that's able to back-power the Pi via the USB-C socket, or power the Pi via GPIO.
This USB Power Delivery negotiation is on the CC1/CC2 lines on the USB C connector, not on the USB signals.
Theo
C't magazine writes in today's edition that the new Pi4 with 8 GB of RAM is available only in the "fixed" version. It may currently be hard to get, though.
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AIUI the issue is just that if you don't use the Raspberry pi branded power supply the Pi may not be able to draw enough power to work.
Just use the proper power supply and you're fine.
-- Brian Gregory (in England).
What is branded?
I bought one Voltcraft QCP-3000 with USB-C cable by HP ... works perfectly well. The cable I bought for another device ... it doesn't matter at all in my opinion.
It doesn't have to be "the Raspberry pi branded power supply", any power supply with the required current capability will do. Actually, more to the point, a USB *cable* which can carry the current without too much voltage drop is necessary.
I was recently setting up a Pi to run continuously as my local DNS server and found most cables couldn't run the Pi satifactorily. That's 'most' as in about three out four cables I tried. I wonder if it's mostly the cable that comes with the "the Raspberry pi branded power supply" is what makes it work [more] reliably.
-- Chris Green
I think it is more like Chinese crap versus made in China quality. The one I bought was HP branded quality USB-C (also made in China)
Not really to do with 'crapiness' or not, a USB lead made for USB-1 or even USB-2 power specifications may well not be good enough to run a Pi.
USB-C is another matter of course.
-- Chris Green
I still think it is about mathematics and technical specs.
2A x 5V = 10W 3A x 5V = 15WIt shouldn't be that hard
The official Raspberry Pi power supply from the RPi foundation. I also use it for my Pis. It's quite cheap (I think mine was 11 Euros).
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Do try and keep up at the back.
-- Brian Gregory (in England).
Both 2A and 3A are well beyond the USB specifications, a 'perfect' USB lead may not be capable of carrying those currents.
-- Chris Green
You are mixing up things
2A/3A are provided by the chargers (well at least in the recent years). What you refer as "beyond" is for the basic standard able to provide the current.
Indeed. I am glad that you yourself caught up, too. Unless there are two Brian Gregorys posting ;)
All I'm saying is that the USB standard doesn't provide even 2 amps. Thus a 'USB' cable that conforms to the USB specification doesn't need to be able to carry that much current.
If a Pi requires more than the USB specification allows then its power supply *and* cable are "more than USB".
-- Chris Green
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