Rock5 does not work on most PD power supplies

#102

I have been bemused by the pd-power from the start and would quite like that to remain a useful available type-c, but hey…

The adapters are cheap and cheerful usually about this price

I posted a 3amp which is 36watt and likely more than enough even with a couple of pheripherals
This time swapped ebay and aliexpress sources just to show how little cost they can be.
You could likely get by with 2amp or if supplying more a 6amp will still give you change from £10

Why pd with a sbc is just a huge question for me but hey I have a lovely 90watt PD now that cost me £30 that I don’t use because I can never guarantee it will boot next time, but also it is so handy to be able to gurantee a 12v rail for so many other computer pheripherals why do I want PD on a SBC?

Would of prefered either a vertiical or rear mounted 5.5mmx2.1mm as also sticking the power into the front panel is not my perference either.
Also while I am at it I will bring up my other gripe of onboard switches and why not simple jumpers that can also be wired switches via duponts like a normal mobo and even be fed by a relay for remote control.

Rock 5B maskrom mode not working
#103

You need PD for higher power sbc units. Absent something like Qualcomm QuickCharge (licensing costs) PD is the way. Most usb chargers max out at 5V 2.4Amp if you’re lucky. the vast majority just pump out 5V 1amp unless they support proprietary standards like Samsung or Qualcomm quickcharge.

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#104

The whole point is you do not need PD at all. PD is great for mobile devices with batteries as one unit can charge all. That is what is good about PD and that is all, god knows how many decades it has been since Telsa but there is nothing new about DC and volts & amps.

All you need is a DC psu and the C in SBC stands for computer and there are standardised voltages 3.3, 5 & 12 up to 1000’s of watts.
SBC have been using 5v wall chargers because they are convenient and cheap not because they are essential.
It worked for Pi because they could use 5.1v direct and it made them cheaper as they didn’t need an onboard regulator.

Small cheap SBC use 5v wall chargers just the same but when you have higher power with onboard buck regulators that will take anything from 5.1-20v any psu with the right connector of those voltages will do.
So why we have a power input, stealing a really handy USB-C that negotiates a voltage that is going to be converted anyway is actually totally pointless as we can not charge something else without losing power to our SBC…

You think we need PD for higher power sbc units, you mean and nope you are wrong.
Just look at how much hassle PD has caused and we could have a better higher current carry connecter in a 5.5/2.1mm jack (which it does have by the pure physics of more contact surface area) of fixed volts from 5.1 - 20v and we would not of had a single problem apart from those not supplying enough amps which can still happen with PD anyway.

#105

You can certainly blame the use of USBc for power on the ubiquity of the Raspberrypi. But I like most people am tired of every damn item needing different power adapters. I’m fine with the option of a DC barrel jack as long as the USBc is still there. Hopefully they fix the PD negotiation bug with booting up. But I certainly would not be buying 2 units if the only power options were dc plug or poe+.

#106

I am also similar as would also like to keep the usb-c being a usb-c and not obstructed with some relatively pointless pd when I have a barrel jack connector somewhere :slight_smile:
I like what oDroid do in this case and think its more simple and industrial.
The consumer choice is sort of weird as apparently 70% of SBC sales are B2B and likely don’t see an advantage in consumer grade multi voltage psu’s.

Same with the onboard switches as why not jumpers, that can also feed wired switches or relays.

But with all the probs all I am saying is if you have a PD then see if it works ok, but if you buying a psu for the SBC just get a dumb 12v (plentifull & cheap) and usb-c adapter and be problem free as PD is not essential.

#107

Thank you. Finally my Rock 5B is working now. :rofl::rofl::rofl:

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#108

Does Rock Pi 4B SATA shield work with Rock 5? That shield accepts 12V with 5521 barrel jack, using a nice step-down converter to provide the Rock Pi (4B) with 5V via GPIO pins.

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#109

So if i dig up a 12v 2amp supply and stick an adapter on it i’m good and wont toast my board? I have several of those power supplies laying around, for external drives and such. Seems i dont have any bits and pieces laying around to build one from scratch. ( while i wait for an OEM one to arrive, i went ahead and broke down and ordered one… 2 weeks out )

#110

12v 3amp is my pref as nice comfortable headroom and will make little diff to price.
But also a USB-C to 5.5mm/2.1mm barrel adapter is needed.

The only thing that Rock5b and a PD do is negotiate a voltage via a software PD trigger the rest is identical where you feed an onboard 5.1-20v rated buck regulator.
You have merely removed the problematic negotiation and set it to 12v and my pref for 3amp is 36watt as try never to push to max as 70% is often a comfortable rating.

Wattage wise 3amp is just a tad more than the PD Radxa have in the shop https://shop.allnetchina.cn/collections/rock5-model-b/products/radxa-power-pd-30w

We are still on the v1.3 schematic but we can even see the exact chip.

The MP8759 as the Monolithic power blurb says is a 26V, 8A, Low IQ, High-Current, Synchronous, Step-Down Converter

If we look at the efficiency curve as the out is 5.148V the max range is 4.5-26v whilst so and 5.1v-20v is a safe working range as we get from PD and low IQ really stands for low quiescent current but there is nothing smart about PD.

Buck
Buck.PNG1071×1171 110 KB

My PD negotiates 20v which is also far less efficient than 12v but doesn’t cause the problems long cable runs of 5.1v does that produces high currents and the need for very thick cables as ampages double to 7.1amps for 36watt.
12v is middle of the road, its a standard PC voltage that gives you a 12v fixed rail USB-C supposedly can supply up to 5amp but 3amp again is that 70% safe margin.
Yeah 12v 3amp in standard operation is likely even more efficient than your PD will choose.

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#111

ordered a barrel to usbC last night. should be here tomorrow. ( only reason i said 2 amp, is i have several of those laying around ) eventually the ‘real’ one will show up.

#112

Yeap then if you already have a 2 amp or a PD then go for it.
The adapter will expect the outrt to be gnd & inner postive as all should be that way but better to check.
Usually there is a liitle diagram showing this on the adapter with the quoted model and specs.

#113

i always use a meter for polarity, i never trust what the side of the device says :slight_smile:

#114

Good as just a disclaimer but to be honnest it would be something weird and wonderful to be anything different but thought maybe I should put the above as a disclaimer :slight_smile:

#115

I ran across a mis-wired PS before. Blew up my device.

#116

Well that was a fail. Got the barrel to usbC today but same results. Found a 12v 5 amp supply ( better than i thought i had in the closet ) but still no boot and the occasional blink back to green from blue.

Both Armbian and OEM builds.

Removed both WiFi and SSD cards, and the eMMC to reduce power needs. Just running off SD, 2 different brands.

I really hope i didnt just get a dud… that will piss me off. I guess go dark on this and just wait until the RockPD supply shows in a week or 2.

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#117

Sorry I didn’t get to warn you sooner. If you check the specs closely on the barrel to usb-c adapter it’s only rated to work for a 5v power supply. That aligns with the user feedback I read.

#118

well shoot. oh well i still have the OEM one coming. i guess i could wire this one up to GPIO if i needed to without cutting any wires as i had a barrel to"breakout" in the same bag as the supply ( didnt remember i had that ).

#119

Ah crap, I did the same thing

Are there any 12v barrel’s to usb-c or GPIO only way to go here? Though it looks like you can only use up to 5v on gpio.

#120

I am using a similar usb-c to 12v barrier and it works fine with my 12V adapter with nvme SSD attached. So this method would work but probably you have to find a different adapter.

#121

Do you happen to have a link to it, having a hard time finding one