
Raspberry Pi Compute Module 3 out now - rbanffy
https://www.raspberrypi.org/magpi/compute-module-3/
======
mcjiggerlog
In case anybody else had no idea what this is:

The Compute Module is a Raspberry Pi in a more flexible form factor, intended
for industrial application.

The compute module contains the guts of a Raspberry Pi (the BCM2835 processor
and 512Mbyte of RAM) as well as a 4Gbyte eMMC Flash device (which is the
equivalent of the SD card in the Pi). This is all integrated on to a small
67.6x30mm board which fits into a standard DDR2 SODIMM connector (the same
type of connector as used for laptop memory). The Flash memory is connected
directly to the processor on the board, but the remaining processor interfaces
are available to the user via the connector pins. You get the full flexibility
of the BCM2835 SoC (which means that many more GPIOs and interfaces are
available as compared to the Raspberry Pi), and designing the module into a
custom system should be relatively straightforward as we’ve put all the tricky
bits onto the module itself.

source - [https://www.raspberrypi.org/products/compute-
module/](https://www.raspberrypi.org/products/compute-module/)

~~~
iamcreasy
Can you give me some example of it's application?

~~~
pi-rat
Let's say that you're trying to create a fancy internet radio for mass
production. You want to base it on linux. Instead of producing a PCB with a
CPU and tons of support circuitry (hard) you can instead include a SODIMM-
connector (easy) and plug in a RPI compute module.

You can get away with a _much_ simpler design and lower production tolerances
by doing this - enabling you to use less time and use cheaper production
techniques.

~~~
kakarot
But does this cost-saving scale?

I was always under the assumption that all-in-one minicomputers were for
prototyping and hobbyist engineering. I reformat my Pi often for all the
little things I want to try.

~~~
hamandcheese
Presumably at a large scale there would be resources available to design and
manufacture a completely custom board -- its the low scale applications this
unlocks that make it exciting.

------
cr0sh
Rather than releasing this, I wish they had instead ramped up production (or
something) of the Pi Zero.

It was supposed to be the "5 dollar Raspberry Pi" \- but instead, due to some
reason, you can't get an Pi Zero for $5 - or if you can, you are limited to
"one per customer".

It feels similar to what happened a while back with the ATMega328P uC chip -
they were being bought up in droves to such an extent that you couldn't get
the IC thru Digikey and others (well, the DIP version - the SMT versions were
almost totally unaffected).

It seems like something akin to ticket scalpers and the like buying all the
tickets in a venue to sell them on to purchasers at a higher price; which is
what I have seen on the Pi Zero - lots available on Ebay and other retailers,
but for a much higher price than "5 dollars".

So people (apparently) are paying this extra cost, and that is what the
"market" sets the price for the board. Even though it was marketed to be the
"5 dollar Raspberry Pi" \- it's true market cost is much greater (in some
cases, you could only get the board with an extended "kit" of materials -
driving the cost up and beyond that of a single bare Raspberry Pi 3).

~~~
khedoros1
My interpretation: The Raspberry Pi Foundation wanted to be able to point to a
product, technically available for $5, as a point of comparison against some
of the super-cheap Allwinner boards. I think the margins are probably thinner
than the larger Pi hardware, and I don't think they've ever intended to make
enough that they'd be available in arbitrary quantities.

~~~
noonespecial
That's my take exactly. They needed an answer to CHiP and Orange Pi stat. When
everything is tabulated, I expect they actually lose a tiny bit on each one. I
even suspect they called it the "Zero" because it was going to be sold for
BOM+Assembly (thus netting zero).

Its an advertisement. Not a product. Giving them away in a magazine was
brilliant.

------
schappim
For those who want the TL;DR;

What has changed:

• Double the RAM (now 1GB, up from 512).

• Now uses the BCM2837 processor

• 1MM thicker

• New 'lite' version which will allow you to use your own SD card (no more
having to fit everything within the 4GM eMMC)

• Pulls more current and will get hotter (just like the RPi3)

• Version 1 is now being obsoleted

What has stayed the same:

• 1 for 1 pin compatible with the compute module V1

• Same 4GB eMMC for the non lite version

Source:
[http://raspberry.piaustralia.com.au/](http://raspberry.piaustralia.com.au/)

~~~
rbanffy
One thing I didn't see in the connector is ethernet. I've been playing with
the idea of building a small cluster and having all machines neatly stacked in
a backplane that could act as an ethernet switch (maybe a KVM for HDMI/USB)
instead of screwed together with board spacers and cables running around the
setup would be awesome.

~~~
nine_k
RPi2 had an Ethernet adapter internally connected via USB2. Probably this is
not what you want for a cluster anyway.

Many competitively-priced ARM boards with proper Ethernet exist.

~~~
rbanffy
Yes, but having a proper ethernet on the edge connector would avoid the need
for an RJ-11 and allow integrating a switch on the board hosting the CMs and
prevent the usual mess with cables forming around the boards.

At least, that's what I'd hope.

~~~
Sanddancer
The Pi has a single USB OTG interface, and no onboard ethernet. On the regular
Pis, that's sent to an on-board hub, which fans it out to the USB sockets and
the USB-Ethernet chips. The Compute Module, on the other hand, doesn't include
a hub and Ethernet chip, because not every application will need it, and
probably more importantly, it can be set to boot off code it receives from a
USB host. This is useful in debugging because you can start working on things
with a very minimal number of connections, and also so you can rapidly
reprogram it without having to reflash for every boot.

In general, the CM has a lot of support for I/O that is just not feasible with
the package the regular PI uses. Things like the extra camera and display
ports can be useful for computer vision packages, but would make routing on
the normal board real difficult. By minimizing the extent of the breakout,
they really do make the chip able to be considered in a lot more use cases.

------
sorenjan
Speaking of Raspberry Pi, what's the chance that we'll see a Raspberry Pi 4
within a couple of months with higher bandwidth I/O, like USB 3? The RPi 3 is
mostly fast enough for most applications, but the slow USB (and ethernet over
USB) makes it unsuitable for networking where any kind of bandwidth is
required, like a simple NAS using an external harddrive.

I guess it comes down to what kind of chips Broadcomm has at the right price
point, anybody here know if it's a possibility?

~~~
Const-me
Not going to be terribly efficient.

There’s no DMA for USB. Meaning, every IP packet has to go through CPU, and
the CPU isn’t that powerful.

Some people tested gigabit USB NICs with Pi 3. Different people measured
250-300 mbit/sec, way lower than USB 2.0 limit 480 mbit/sec. I think the CPU
was the limiting factor there, not the USB.

~~~
sorenjan
Doesn't really need to be terribly efficient, good enough will do for the
price.

One issue is that there's only one USB port on the board, and the external
ports and the ethernet port are connected through a hub. So when you connect
an external harddrive and try to transfer data over the network you end up
with < 10 MB/s transfer speeds.

If Broadcomm decided to use DMA for their USB that would of course be ideal,
but I don't know if they have any suitable products like that.

Of course 4K and h.265 video decoding would be welcome too for a lot of users.

~~~
Const-me
Apparently, Raspberry markets their products as affordable but still useful.
The features you’re asking for are currently way too expensive for that
market.

Single-board computers with USB 3.0 and capable of 4K playback are available,
but they cost $200 or more: Nvidia Jetson TK1, Inforce 6540, etc.

~~~
justin66
But that just begs the question: does Broadcom have any parts on the shelf
such that, if they tweaked them and sold them to the RPi project at cost,
they'd fulfill those requirements? Broadcom and the RPi project can do some
things in conjunction that Nvidia, for example, cannot.

~~~
Const-me
Looks like the answer is yes, this chips are sold for $20:
[https://www.broadcom.com/products/broadband/set-top-
box/bcm7...](https://www.broadcom.com/products/broadband/set-top-box/bcm7251)

However I’m not much into the hardware design, I only write some embedded
software for those things. Might be reasons why it’s still too expensive: if
the chip requires too many layers in the PCB, too many external components
(like RAM), too much electrical power so it needs better PSU and some cooling,
and so on.

------
robin_reala
>The Compute Module 3 will be used in NEC’s new range of smart, large-format
displays

That’s interesting. Upgradable CPUs in a TV? I know it’s been done before, but
never trivially or cheaply.

~~~
nom
You don't use these kind of CPU modules for the upgradeability but rather to
save time and money - it contains most of the highly integrated components
needed in a smart device. You only have to design a mainboard around it,
containing the few components you need.

I find it rather curious that they opted to use it in a TV, considering that
they probably have to place BGA components on the mainboard anyway, to drive
the display. Using CPU modules mostly pay off in simple products (think: a
couple of switches, LEDs etc).

~~~
mschuster91
> I find it rather curious that they opted to use it in a TV

Guess that NEC wants to market itself to the hacker space. Which is a
marketing strategy that works for me - I'll be getting one as soon as they're
available. I mean, a Smart TV running Debian? That's just plain cool.

~~~
jon-wood
I think this isn't really about marketing themselves to the hacker space, and
probably more about not having to develop their own processing hardware.
Depending how the pins are hooked up you could probably swap the compute
module out for a stock one and run Debian, but the core focus will be on NEC
being able to provide the software for digital signage alongside the hardware.

~~~
wyager
If that were the sole motivation, I doubt they would leave the raspi
accessible as in the picture.

~~~
jon-wood
Making it accessible means that they can easily sell upgrades.

------
jsingleton
Their blog post has more info: [https://www.raspberrypi.org/blog/compute-
module-3-launch/](https://www.raspberrypi.org/blog/compute-module-3-launch/)

I posted this link earlier but it didn't attract much interest.

------
JohnBooty
I've always been so confused by the smallish amounts of RAM available on
rPi's.

Certainly, 1GB is more than enough for many applications. And obviously low
cost is a primary requirement.But a rPi with more RAM would open up so many
more use cases - databases, Redis instances, various caching applications.

If I'm not mistaken, there are quite a few other single-board computers
(Beaglebone, Intel perhaps...) that offer more RAM. However, Raspberry Pis
have a long lifecycle and excellent community, which is appealing.

I think this must be a very deliberate decision on their part. It would make
sense to me, I guess: their mission is clearly to serve the education and
hobbyist markets and that mission would be compromised if they create
something that IT departments begin to buy in droves.

~~~
russellbeattie
I just wish they'd put a damn real time clock and watch battery on the thing
so it wouldn't lose time. It's like two chips... hell, I'd be happy to buy the
battery myself.

------
nom
@HN: Has anyone here used their modules in a product?

~~~
pawadu
I have the same question!

I don't really understand where this could be usable and I would rather see
the pi foundation use their resources to upgrade and sell more Pi Zeros!

~~~
pjc50
Linked through this post is a blogpost about using them in space:
[https://www.raspberrypi.org/blog/compute-module-
cubesats/](https://www.raspberrypi.org/blog/compute-module-cubesats/)

The compute module exists due to customer demand - the regular Pi is not so
easy to embed in another device.

~~~
intoverflow2
That doesn't seem to be the point of these though. They seem to be intended to
use in products (and it's still a bit too expensive and unreliable to make
that feasible)

------
teekert
Man would I like a Pinebook arm like device powered by this compute module.

------
nfriedly
It looks like it doesn't have Wi-Fi (?)

~~~
Kliment
Indeed, it seems to have neither the combined BT/Wifi IC of the pi3, nor the
antenna. I guess there was no way to do it and keep backward compatibility as
the original compute module had one of the sdio interfaces brought out to the
connector. On the pi3, one of the SDIO interfaces is brought to the wifi IC
and the other one to the microSD socket. On this compute module, one is
brought to the connector and one to the built-in eMMC storage. Presumably it's
possible on the light version with no built-in storage to add a board/module
that does wifi (can't add the chip directly because it only has an emmc
footprint). Maybe they'll end up doing that later on, have a revision that has
onboard wifi but no storage. I don't know how useful that would be though.

~~~
james_a_craig
Unfortunately, there's two SD interfaces on the board, and the one that does
eMMC (or the SD card on a normal Pi) can only do storage and can't do SDIO.
The 2nd interface is used for the wireless on the Pi 3, but that one's brought
out externally on the CM, so you can't really do that.

The answer is to put the wireless on the carrier board for the CM, of course,
but that's awkward because of the regulatory requirements on wireless bits.

------
dlee12
A little off topic, but any suggestions for which raspberry pi to purchase?
This would be my first one and I am very excited about starting some sort of
side project with it (using either Go or Python). I see a lot of starter kits
on Amazon, but not sure what the difference is between them. Has anyone had
any luck with these? Thanks :)

~~~
dtparr
CanaKit and Vilros are the ones I see recommended most often. I went with
this[0] Vilros one so I could choose my own sd card, and was pretty pleased
with it since it had everything else I needed (already had a spare
keyboard/mouse etc.)

[0] -
[https://smile.amazon.com/gp/product/B01D92SSX6/ref=od_aui_de...](https://smile.amazon.com/gp/product/B01D92SSX6/ref=od_aui_detailpages00?ie=UTF8&psc=1)

------
IgorPartola
Now if only someone provided colo or leased versions of these. I imagine this
is a better value prop than most VPS's.

~~~
hedora
Scaleway has a 3 euro/month ARM baremetal (and Intel VPS) offering that is
higher end than a raspberry pi 3, at least in terms of ram, network + storage
-- didn't check CPU.

[https://www.scaleway.com/pricing/](https://www.scaleway.com/pricing/)

[edit: baremetal arm, not vps arm...]

~~~
bedros
any feedback on using this service?

~~~
IgorPartola
I use it currently. It's mostly good. They have SAN storage, so you are not
limited by what's attached to the thing directly and you also get reliability.
The control panel is mostly good. The boxes are speedy and bandwidth is good.

The bad: their ARM boxes don't get IPv6. At all. The VPS's get 16 IPv6
addresses, which is really dumb.

The badder: their ARM boxes _and_ their VPS boxes can't be shut down. You can
reboot them, or you can save their local state into block storage, which even
for a small box takes many hours (up to a day in one instance for me). You
also can't force-detach a volume from a box, so if say your box/VPS got
borked, but you had a data volume you want to save, you are SOL.

~~~
xyzzy_plugh
Can you at least halt?

~~~
IgorPartola
I don't believe so. They just boot back up.

------
LeoPanthera
I always wished there was a Psion 5-style palmtop computer that used the
compute module as brains.

~~~
CliffyA
I have too, but I dream for more of an OQO style. I've wondered at some point
how difficult it would be to get a quality case created that all the parts
could go into.

------
jzawodn
Does anyone sell a "breakout" board for it that will allow you to power it
externally and get access to most of the pins?

~~~
privong
The announcement post says there are breakout boards available:

> An updated IO breakout board (CMIO3) has also been launched, which will
> accept all three models. You can purchase yours from element14 or RS
> Components.

~~~
jzawodn
Oh, wow. How did I miss that before? Cool. Thanks!

------
oveddan
What kind of gpu does this have?

~~~
ZenoArrow
The same one as the Raspberry Pi 3, it uses the same Broadcom SoC.

