Comment by schappim | Hacker News Reader

Comment by schappim | Hacker News Reader

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What's the same:

- Same Broadcom BCM2835 Chipset

- Same 512MB RAM

- Same full size HDMI port

- Same 10/100 Ethernet port

- Same CSI camera port and DSI display ports

- Same micro USB power supply connection

What has changed:

- Now comes with 4 USB ports so you can now connect more devices than ever to your Raspberry Pi.

- There is a 40pin extended GPIO so you can build even bigger and better projects than ever before. The first 26 pins are identical to the Model B to provide 100% backward compatibility for your projects.

- Micro SD slot instead of the full size SD slot for storing information and loading your operating systems.

- Advanced power management:

-You can now provide up to 1.2 AMP to the 4 USB ports

– enabling you to connect more power hungry USB devices without needing an external USB hub. (This feature requires a 2Amp micro USB Power Supply)

- The B+ board now uses less power (600mA) than the Model B Board (750mA) when running

- Combined 4-pole jack for connecting your stereo audio out and composite video out

(Source: http://raspberrypiaustralia.com.au/products/raspberry-pi-mod...)

[Edited for formatting]

I'm still missing a normal round power plug, as the ramshackly micro USB draws much more power then the allowed 500mA.

Also Ethernet is still connected via USB, and horrible slow.

Most mobile devices draw much more power than 500mA over micro USB as well, I was assuming this was in-spec now, it certainly seems to work fine. And many people have spare 1A+ chargers lying around as mobile devices tend to break before their chargers (ramshackly plug notwithstanding). Those chargers are usually really tiny, as well.

So I think micro USB is a fine choice. It also lets you draw from the fairly rich ecosystem of other USB power gadgets such as external batteries. I'd be really annoyed if they switched to a "normal" round plug.

It will work fine in 95% of the cases, but 5% will ruin their computer USB port, because the PI is not within the specs. The PI not only draws 750mA (old) or 600mA (new) when idle, but much more, if you attach SSD, and USB devices.

The ramshackle micro USB port is a nogo for me.

You don't have to power it from the USB port. You can supply juice to the 5V and GND pins on the GPIO header. That's probably a better power inlet interface than either a ramshackle micro USB connection or a janky barrel plug.

reread the usb spec. it will not ruin the USB port.

Some really old computers have physical fuses on the USB ports that can - and will - blow if you draw too much power from them.

Should probably upgrade, then, before spending more money on Raspberry Pis.

I'm not aware of any spec requirements for overcurrent protection on the host ports (devices have strict power behavior per spec), though they may be there.

I am aware, however, of countless USB host designs that simply put a 5v regulator rail on the power line and could probably be induced to overheat by a misbehaving device.

It's definitely in the USB 1.1 spec, (with some verbiage that excessive current draw on one port is not allowed to affect other ports) though they may have relaxed it later. I have several old Belkin hubs that will terminate (with prejudice) power to any port that draws over 550 mA, until you physically power-cycle the hub. This is annoying for obvious reasons, especially on 7-port hubs with beefy power supplies, so most hub manufacturers don't do that anymore.

What the pi should do is monitor the voltage level of port it is drawing from, if it draws it down, it should turn on a fault LED or disable onboard services (like ethernet and usb).

The whole point is that most people (especially the target market) have a spare USB charger hanging around. The Pi takes exactly the same connector as your mobile phone - it's one less bit of kit to buy.

The Ethernet chip is a new one tho - maybe it's a little less terrible?

(No idea - my applications for the rpi don't depend on it being a speed demon on the network.)

The Ethernet speeds are limited by both the USB bus it's riding on, as well as the slow CPU processing power.

Although, for most of my projects so far, it's been plenty fast.

Any recommendations for similar small/cheap devices with better Ethernet?

Have a look at the Beaglebone Black.

the ethernet chip seems to just be the 4 usb-port version instead of the 2 usb-port version.

But as far as I read, the PI can still not boot over Ethernet, which is a requirement for me to boot into backup cycle (Installation = Restore), and it still can not wakeup on LAN.

If you load U-Boot onto an SD card, the rPi can be configured to use that to boot over Ethernet. It's not a completely "pure" network boot, but that's impossible given the hardware. (There's simply nowhere for a bootloader to live besides the SD card.)

You need some sort of bootloader, even in a traditional PXE boot scenario... it's just that your BIOS hands off to the bootloader on your onboard PXE chip instead of to your OS's bootloader, etc. So, it's chain-booting no matter how you slice it.

You can setup your SD card to have U-Boot and not much else... just what's necessary for U-Boot to, well, boot. Then it takes over and does it's network boot of your full OS. So you can get a sort-of PXE boot setup.

Yes I agree, the Ethernet is the one thing (other than the price in Australia) that stops me from using a pi

-You can now provide up to 1.2 AMP to the 4 USB ports enabling you to connect more power hungry USB devices without needing an external USB hub. (This feature requires a 2Amp micro USB Power Supply)

Nice. In my experience, using a good power supply for the pi (instead of cheap ones selling for 5 bucks on ebay) is mandatory also in the current revision, and solves a lot of problems with video and USB devices (for example, cellular modems).

The Apple iPad charger works wonders.

The Pi Shop sell a high power adapter http://www.amazon.co.uk/Adaptor-Supply-Charger-Tablet-iPhone... with full 2A and dual USB ports.

The Samsung chargers as well, LG chargers unfortunately just only give 0.8A

Current != power. I recommend altering this to say "uses less power (600mA at X volts) than the old (750mA at Y volts)," filling in X and Y with the voltage that the systems run at.

Or: "uses less power(X mW) than the old one (Y mW)," filling in X and Y wit hthe power that the systems run at.

Power = Current * Voltage so just giving the voltage doesn't help either. I believe the voltage is unchanged so stating a decrease in amperage would suffice.

Right now it's possible to back feed power with a powered hub instead of using the micro USB connection. I'd like to see the schematic to find out if that's still possible, but I can't find one yet.

Here you go (schematic): https://learn.adafruit.com/introducing-the-raspberry-pi-mode...

This isn't a good idea though I've heard, don't you bypass some important components for power safety in the micro USB power circuit?

You're bypassing a fuse. If you have a crappy powered hub that isn't well regulated you could fry your pi.

In reality, the chance of that happening is very small, and safety here is only in the context of the "safety" of a $35 board. Most hubs won't let you draw more than a couple of amps anyway.

Well, I'm not sure how well regulated my $3 powered usb hub is. I find myself having to do this weird ritual of plugging stuff in under the correct sequence otherwise I get some power from the hub and the pi won't boot fully (goes into a weird boot loop).

This is quite the impressive release. The additional USB ports are a welcome addition, as-is the additional GPIO. I have one project in particular that will benefit from the additional GPIO.

The microSD slot is also a big deal. microSD's are much more common now-days than SD's due to most people's phones having them. I own a slew of old mSD's from old phones and can re-purpose them into a Pi project now :)

The microSD card and changes to the ports (more flush USB) also reduce the footprint which means I should be able to cram a new version of my Pi motion activated camera into a smaller waterproof case. This makes me very happy. The lower power demands may also let me get away with using a smaller battery and solar panel.

Agreed. Big win on the microSD. They are also becoming very affordable, especially < 32GB

plus better mounting.

Have them fixed the broken USB system? (USB and Ethernet share the same bus problem)

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