Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Raspberry Pi admits to faulty USB-C design on the Pi 4

arstechnica.com

Post reply on HN
Print view View original

131–140 of 165 posts

Re: Raspberry Pi admits to faulty USB-C design on the Pi 4

#131

Post by ageofwant »

hadlock wrote: post #87
jbarberu wrote: post #11

While this isn't great, as a consumer I don't really see too big of a problem. If I get a raspberry pi to use for home automation or as a media center, do I really need it to work with every USB-C cable? I'd think I'd just find one that works and let that be the dedicated raspberry 4 cable. If you're building a product based on Raspberry Pi that you're selling to others, then sure I could understand the outrage.

Generally when I use a SBC like a raspberry pi or esp 8266/32, I use an existing cell phone charger + whatever cable is nearest to where I'm sitting. I 100% expect the SBC to work with any combination of charger and cable. I have lots of existing cell phone charges and cables so unless I were purchasing this for someone else I don't think I would consider ordering the branded raspberry pi charger/cable. Compatibility…

And you would be disappointed. 3/4 of the micro-usb cables I purchased of my favorite purveyor of cheap chinesium does not power a pi3, and when it does brown-out

Have a hard look at the simple 'how can anyone possibly get a piece of wire wrong' cable, or even better test it.

https://www.youtube.com/watch?v=n70N_sBYepQ

Re: Raspberry Pi admits to faulty USB-C design on the Pi 4

#132

Post by [deleted] »

Someone wrote: post #126
m463 wrote: post #112

Earlier quoted context omitted.

That said, the serial cables that preceeded USB had very simple specs that put the brunt of interconnection complexity on the user. 7 bits even parity? 8 bits no parity? hardware or software flow control? how do I know the modem is connected? lots o' fun!

”had very simple specs” The specs weren’t that simple (why would a serial port connector need 25 wires?). It’s more the implementations that were simple, going down to 5, 3 or even 2 wires ( https://en.m.wikipedia.org/wiki/RS-232#3-wire_and_5-wire_RS-... )

[deleted]

Re: Raspberry Pi admits to faulty USB-C design on the Pi 4

#133

Post by TheRealPomax »

thijsvandien wrote: post #3

Reminder to self: being an early adopter sucks virtually always. Edit: Sure, the issue is rather easy to circumvent, but anyone would have preferred not to have it. At the very least, it affects the resale value. My point is that whenever the answer to the question 'do I need it absolutely right away?' is no, it's better to wait a bit, no matter how much you intend to buy it at some point.

I'm not sure I understand the concept of "resale value" when it comes to a Raspberry Pi... they're dirt cheap boards, who's going to look at one and go "this is a wise investment that I will be able to sell on a year from now at a good price"?

Re: Raspberry Pi admits to faulty USB-C design on the Pi 4

#134

Post by TheRealPomax »

dividuum wrote: post #34
tjohns wrote: post #30

Earlier quoted context omitted.

Yes, but it's an extra expense. If you've got spare USB-C chargers you could use, it's tempting to wait.

Their USB charger costs 7€. From my experience: Just buy their charger and you'll have no problem. I've seen so many attempts at powering the Pi with alternative sources that suck and cause problems. 7€ is worth avoiding that.

Remember when the EU had to pass laws to prevent everyone from making their own bloody chargers with proprietary plugs for mobile phones, because _no one needs their own custom charger_? Yeah, that.

It doesn't matter how cheap their charger is, no one should need to even buy one. RasPi botched their USB-C implementation, and the solution to that is not "buy yet another charger", it should be "we're fixing the design immediately, and it's going to cost us a fair bit but you can send your board back to get it replaced"

Re: Raspberry Pi admits to faulty USB-C design on the Pi 4

#135

Post by Narishma »

giobox wrote: post #122
groovybits wrote: post #33

From a Pi consumer perspective, this is not that big of a deal. However, it damages the purpose (in name) of USB C. Isn't C supposed to be the 'all purpose' spec? If we have popular manufacturers failing to follow the spec, we end up with cables marked as 'compatible with Raspberry Pi' or 'compatible with Nintendo Switch'. To the average consumer (and even most techies), USB C was supposed to be the 'one size fits al…

I find it incredible that presumably no one tried using a MacBook charger before this shipped. If they did and didn't document the shortcoming that's arguably just as bad. Surely a not insignificant number of customers have MacBooks? If I was writing some test specs this use case would almost certainly feature, given the MacBook Pro's USB C adapter must be one of the most widespread high power USB C charger designs i…

You over-estimate how popular Macbooks are outside the US.

Re: Raspberry Pi admits to faulty USB-C design on the Pi 4

#136

Post by DuskStar »

teilo wrote: post #72
loeg wrote: post #46

Earlier quoted context omitted.

This has always been a criticism of USB C and it proves true time and time again. USB-C tries to be too many things to too many people and ends up with a huge matrix of incompatibility as a result.

And the criticism is completely invalid here. The power spec is very clear and unambiguous, and there is only one way to get it right. It is not the fault of the spec when manufacturers cannot be bothered to produce a circuit that has already been designed for them in the spec itself.

> The power spec is very clear and unambiguous, and there is only one way to get it right.

Obviously not, since there is a way to get it almost right, which is what the Pi 4 demonstrates here. Experience from cryptography suggests that for a spec to be truly unambiguous, any deviation should make the implementation fail obviously in as many situations as possible.

Re: Raspberry Pi admits to faulty USB-C design on the Pi 4

#137

Post by petecox »

giobox wrote: post #122
groovybits wrote: post #33

From a Pi consumer perspective, this is not that big of a deal. However, it damages the purpose (in name) of USB C. Isn't C supposed to be the 'all purpose' spec? If we have popular manufacturers failing to follow the spec, we end up with cables marked as 'compatible with Raspberry Pi' or 'compatible with Nintendo Switch'. To the average consumer (and even most techies), USB C was supposed to be the 'one size fits al…

I find it incredible that presumably no one tried using a MacBook charger before this shipped. If they did and didn't document the shortcoming that's arguably just as bad. Surely a not insignificant number of customers have MacBooks? If I was writing some test specs this use case would almost certainly feature, given the MacBook Pro's USB C adapter must be one of the most widespread high power USB C charger designs i…

It seems a case of rushing a product 9-12 months ahead of schedule, scrapping two silicon revisions, as mentioned in the announcement[0] in their haste to be "production ready".

"Good, low-cost USB-C power supplies (and USB-C cables) are surprisingly hard to find, as we discovered when sending out prototype units to alpha testers"

In hindsight that reads that they tried a bunch of off-the-shelf cables and were perplexed about why some of them didn't work.

So they built their own official power supply that worked around the design flaw.

[0] https://www.raspberrypi.org/blog/raspberry-pi-4-on-sale-now-...

Re: Raspberry Pi admits to faulty USB-C design on the Pi 4

#138

Post by Taniwha »

addicted wrote: post #120
umvi wrote: post #73

Earlier quoted context omitted.

USB in general seems like a deep, deep rabbit hole. You could devote your entire career to becoming a USB expert. The USB 2.0 spec is like 700 pages long. The 3.0 spec is like 500 pages long and requires you to be familiar with the 2.0 spec at the very start. I started digging into USB for a project and the rabbit hole kept going deeper and deeper; I never fathomed the amount of complexity hidden under the hood of US…

The number of pages don't tell you anything though. I'd assume there are a bunch of reference designs, probably provided by the USB consortium itself, which should make it unnecessary to know anything about the spec to produce a USB C port.

There are open source designs (that I've successfully copied) that show how the RPI people should have done this correctly, it's not hard - in this case they tried to save a 0.1c resistor

The hard bit is fitting all those traces (some potentially high current) around that dinky connector with 24+ ground pins - with many all trying to do the swap thing at the same time

Re: Raspberry Pi admits to faulty USB-C design on the Pi 4

#139

Post by giobox »

Narishma wrote: post #135
giobox wrote: post #122

Earlier quoted context omitted.

I find it incredible that presumably no one tried using a MacBook charger before this shipped. If they did and didn't document the shortcoming that's arguably just as bad. Surely a not insignificant number of customers have MacBooks? If I was writing some test specs this use case would almost certainly feature, given the MacBook Pro's USB C adapter must be one of the most widespread high power USB C charger designs i…

You over-estimate how popular Macbooks are outside the US.

About two thirds of all Apple's computers are sold outside the US. It's significant enough. In British engineering circles there are plenty of them (relevant given the location in which the Pi team works).

The key point here is the standard charger design used on almost all laptop models from the world's 4th largest computer vendor. In my experience laptops from the top three have nothing close to the level of standardization in their charger design, given none of the top three have standardized solely on USB C for laptop charging. It was entirely foreseeable many people would try this and be disappointed when it didn't work.

Re: Raspberry Pi admits to faulty USB-C design on the Pi 4

#140

Post by stordoff »

jakobegger wrote: post #63
CriticalCathed wrote: post #39

Earlier quoted context omitted.

USB C has confused me for the same reason. I read often about how there is no expectation that two USB-C cables/ports will work together. Why design them to fit together if they won't always work right?

Because it's useful to have a bunch of multi-purpose ports on a computer. You can attach a mouse, a keyboard, a printer, a hard drive, a screen, a dock, a charger, or whatever you want, all to the same port. In my experience, finding the right cable has never been an issue. All the USB-C devices I've bought came with a suitable cable in the box.

> In my experience, finding the right cable has never been an issue. All the USB-C devices I've bought came with a suitable cable in the box.

Which is fine, until you need you need a new cable. When I lost the cable for my phone, finding a cable I could trust was a pain.

Post reply on HN