Raspberry Pi Forums

Posted: **Wed Mar 25, 2015 5:59 pm**

rahlquist wrote:
bullen wrote:Also, to put a nail in the OP coffin, RPi 3 will certainly have USB type-C for power and ethernet?
Wouldn't count on that. That would require 1 of 2 things.

1. Manufacture RPi with usb 3.x and deal with the associated costs, does Broadcom make a Pi'esque chip with USB 3? Say the BCM 7445 for example, does support it on chip for example(I dont know if this could even be used to build a Pi compatible device)? Are there extra license costs with usb 3.x?

2. Figure out how to use a USB 3.x connector with a USB 2.0 controller.

For the next 4-10 years the micro usb connector will stay dirt cheap, something the Foundation might find to nice a deal to pass up. The problem is everyone wants to Pi to be perfect for their wants and its not about that, its about a cheap educational product. One of my friends was torqued because web browsing on Pi2 is still sluggish and I explained that to him again.

I don't think that follows.

If the power requirements (even optional additional power) go up, the current will exceed the rating for the microUSB connector. Since we're talking about a *power* connector, there is no logical connection to SoC support for USB 3.

The real fly in the ointment I see for using a USB-C connector is that the spec requires a chip in every cable, which is rather pointless in a power cable. Just wire it so that the power is correct no matter which way it is inserted and only wire the power pins.

Posted: **Wed Mar 25, 2015 8:00 pm**

this would be desirable:
USB hardware cannot be set to client mode

---
The UniFi®Switch features auto-sensing IEEE 802.3af/at and 24V passive PoE to power multiple devices on the network.

http://www.adafruit.com/products/184 (20V max)
mounting holes distance, of course, not same?

Posted: **Wed Mar 25, 2015 9:30 pm**

What are the female plugs that fit the GPIO pins called?

I need to build a mesh of those!

Posted: **Wed Mar 25, 2015 9:46 pm**

bullen wrote:What are the female plugs that fit the GPIO pins called?

I need to build a mesh of those!

Either 20x2 way header sockets (for connecting to a PCB) http://www.ebay.co.uk/itm/231501545458
or 40 way IDC connectors (for use with cables) http://www.ebay.co.uk/itm/111477185272

Or you could use the individual Dupont connectors or just a few wires.

Posted: **Sat Mar 28, 2015 11:45 pm**

Ok, I think I got the best solution:

x4
+

+

=12$

Posted: **Sun Mar 29, 2015 2:17 am**

here also some progress for best solution on horizon!
Some even suggest to glue splitter cable to avoid misuse, but for now it is best to use surface mount box which would offer Ethernet, 2xUSB power and 24V.

Now is clear that in future there could be few USB Ethernet HATs(one completely passive powered 12V and one 24V with resistance detection).
Such module will need to refuse 48V if connected to "real" switch:
http://www.ti.com/lit/pdf/slva664
The objective of this circuit is to provide an accurate 5-V supply at the output of the DCDC converter and disconnect the supply voltage of the converter in case the supply exceeds the maximum recommended operating input voltage of the TPS62130.

In the current example the TPS62130 should be protected against overvoltage at its input. The protection should be capable of handling an input voltage up to a maximum of 40 V (VINmax). The nominal operating input voltage in this example is in the range from 12 V up to 16 V.

---
one of PoE Out profiles can be for each PoE Out enabled port individually:

auto - detection is done regarding resistance on the spare pairs to check if port has PoE capability. For port to be turned on measured value should be within range from 3kΩ to 26.5kΩ;
on - PoE Out is enabled on the port regardless of the resistance on the port. Use this with caution as that can damage connected equipment;

Code: Select all

[admin@MikroTik] > interface ethernet poe monitor [find]
              name: ether2 ether3 ether4 ether5
   poe-out-voltage: 23.2V  23.2V  23.2V  
   poe-out-current: 224mA  116mA  64mA   
     poe-out-power: 5.1W   2.6W   1.4W

So far, less than 1% of our customers, as far as we know, have damaged their equipment.
VoIP technician plugged a consumer-grade 5-port PoE switch into a jack that was patched back to a $4000 48-port PoE switch. My previously over-provisioned network closet is now slightly under-provisioned.. and smells like burning

Posted: **Sun Jan 22, 2017 11:55 pm**

Here's a good reason for POE

https://blog.mythic-beasts.com/2016/08/ ... i-netboot/

Posted: **Mon Jan 23, 2017 7:50 pm**

Thread is a bit old, now there are neater solutions:

https://www.amazon.co.uk/Raspberry-micr ... B0108TD78Y - £16.95

or

http://uk.rs-online.com/web/p/lcd-monoc ... s/8977141/ PoE HAT - £30

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