A new day is upon us, and it is glorious. After all, it’s not often that a new Raspberry Pi board is released. As you’re probably aware, the current iteration of the popular Raspberry Pi microcomputer is the Raspberry Pi 3. It has a Broadcom BCM2837 System-on-Chip (SoC) which features a quad-core processor clocking in at 1.2GHz and is supported by 1GB of RAM. Pretty impressive given the size and cost of the device, not to mention the enormous software stack and community resources that are behind it. As we said, you’re probably already aware of this, but what you may not know is the Pi 3’s little brother; the Raspberry Pi Compute Module.
The original Compute module was released in 2014 and was designed to bring the power and versatility of the Pi to a smaller form factor which was better suited to industrial and commercial applications. By stripping away all of the hardware ports and leaving the raw BCM2837 with all the required supporting circuitry, it allowed developers and designers to pick and choose what features they wanted to implement, along with breaking out the full potential of the BCM2837 chip. It had the same specs as the Pi boards did then which was only 512MB of RAM and approximately 10x less processing power than the Pi 3.
But believe it or not, 2014 was 3 years ago now, and 3 years is an eternity in the tech world. So Raspberry Pi gave the Compute Module an overhaul to bring it up to spec with the Current Raspberry Pi 3. So the new Compute Module 3 (CM3) brings a spec bump, and an addition to the Compute Module 3 family in the form of the Compute Module 3 Lite (CM3L).
So today we’re going to be taking a look at the Raspberry Pi Compute Module 3 Development Kit which bundles both a CM3 and a CM3L board, power supply, microUSB cable, CSI/DSI adapter boards, and the all -important Compute Module 3 IO board which breaks out the DDR2 SODIMM package and provides expanded peripheral connection. Now the big question is, is it any good?
Before we dive in, it’s important to keep in mind that the Pi Compute Module 3 is not designed to be used in the same way a Raspberry Pi 3 is. It’s designed for more advanced users such as industrial designers, commercial engineers, and ambitious DIY’ers. That said, it’s not overly complicated to get started with as far as development boards go, and if you do wish to try it out, we’ll provide plenty of information and tutorials on how to go about that.
This article isn’t a setup guide or getting started guide, that’ll come later, for now, we’re going to be taking some first impressions and looking and what’s good, and what’s not so good.
Let’s take a look.
The Good
Stable and Mature Platform
The best thing about the Raspberry Pi Compute Module 3 is that it is a Raspberry Pi. It’s a mature platform and has been tested and refined by millions around the world. The Raspbian operating system is stable and snappy, with the new Pixel update giving a truly modern UI. Once it’s up and running, the CM3 runs just a well as the Pi 3, which is a very good thing (the Pi 3 is awesome!).
Micro Form-Factor
The CM3’s DDR2 SODIMM form factor makes it incredibly easy to implement into designs as sockets are readily available and cheap, and whilst the CM3 is an extra millimetre taller than its predecessor (30mm vs 31mm), it’s still only a third of the surface area of the Pi 3 (Model B+) and being less than 4mm thick, it’s as slim as they come. The total dimensions are 31mm x 67.6mm x 3.7mm.
Supporting Circuitry and Peripherals
Speaking of implementation, if you’re looking at using the CM3 or CM3L in a design, you’ve already got a solid platform with all the required supporting circuitry onboard. You don’t have to worry about the complex design of using the BCM2837 from scratch but instead, can focus on expanding the peripheral ports as your project requires. The BCM2837 actually supports more hardware peripherals than the standard Pi 3 has accessible (due to size constraints), so all 200pins of the SODIMM edge connector breaks out power along with:
- 48x GPIO
- 2x I2C
- 2x SPI
- 2x UART
- 2x SD/SDIO
- 1x HDMI 1.3a
- 1x USB2 HOST/OTG
- 1x DPI (Parallel RGB Display)
- 1x NAND interface (SMI)
- 1x 4-lane CSI Camera Interface (up to 1Gbps per lane)
- 1x 2-lane CSI Camera Interface (up to 1Gbps per lane)
- 1x 4-lane DSI Display Interface (up to 1Gbps per lane)
- 1x 2-lane DSI Display Interface (up to 1Gbps per lane)
CM3 vs. CM3L
The Compute Module 3 and the Compute Module 3 Lite are almost identical in every way except that the CM3 has 4GB of eMMC flash storage, whereas the CM3L does not. Instead, the CM3L breaks out the bus pins for the SD/eMMC so that you can implement your own storage off-board. Depending on your application, the onboard storage might be perfect, whereas, for high storage scenarios, it would be limiting, and more advantageous to implement external storage.
Compute Module 3 IO Board
In order to use/develop with the CM3 or CM3L, you’ll need the IO Board which breaks out all the pins and has connections for HDMI, power, USB, camera and displays, plus more. It’s a fantastic board, and well designed, however, the drawback is that unless you already have a physical implementation for the CM3/CM3L, the module itself is useless without the IO Board.
Price
The CM3 and CM3L are both cheaper than the Pi 3 thanks to their simpler design. Indeed you can get the CM3 and CM3L for $46 and $55 (AUD) respectively, which gives all of the power of the Pi 3, with even more design flexibility.
The Bad
There really isn’t a lot of criticism for the Compute Module 3 platform. Both the CM3 and CM3L are fantastic bits of gear, with both suiting a slightly different purpose. However, there are a couple of points to keep in mind when purchasing the CM3/CM3L, which aren’t necessarily negative but are important to take note of.
Price of IO Board
Whilst the modules themselves are cheap, the Development Kit which comes with everything you need to get started will set you back $365 (AUD). However, this is actually not that bad given that it contains everything you need to get started, and a CM3 and a CM3L board.
Complexity vs. Traditional Pi
Not necessarily a bad thing, but due to the nature of its design and its target market, the CM3 has an extra layer of complexity to getting started. Indeed whilst with the CM3L you can use the MicroSD card you use with a Pi 3, the CM3 has built-in eMMC storage which needs to be flashed with an OS before it can be used. It’s fairly straightforward to do (we’ll have a tutorial up soon!), but it’s all something to remember.
Summary
Good
- Stable and mature platform
- Compact form-factor
- All supporting circuitry is provided and all peripherals accessible
- Two different options: CM3 and CM3L
- Fantastic development board
- Low-cost modules
Bad
- Added setup complexity
- -Price of the IO Board
Our Verdict
The Raspberry Pi Compute Module 3 and 3 Lite are fantastic and worthy additions to the Raspberry Pi family. They provide the increased flexibility that designers and industrial users are looking for, whilst making the benefits still accessible to makers. The Development Kit, whilst more expensive than the modules, comes with everything you need to get started and rounds out the options for what’s already an incredibly user-friendly and stable platform. The Raspberry Pi Foundation have nailed it!
Be sure to check out our tutorials and projects modules for more information on using the Raspberry Pi Compute Module 3 platform and great project ideas.
