The Raspberry Pi Foundation unveiled the $30 Raspberry Pi Compute Module, an embeddable computer-on-module version of the Pi, plus a companion baseboard.
With the huge popularity of the Raspberry Pi, it was inevitable that an embedded version of the Pi would eventually emerge. Now, hackers, experimenters, and embedded development pro’s have an inexpensive and robust way to embed Raspberry Pi compatibility in a vast array of gizmos, gadgets, and IoT (Internet of Things) projects without resorting to a tangle of interconnection cables and expansion cards. Thanks to this new computer-on-module (COM) version of the Pi, projects can benefit from the Raspberry Pi’s open-source OS and application software, as well as from its expansion board (“shield”) hardware designs, many of which are similarly open-sourced.
Raspberry Pi Compute Module (left) and SBC, roughly to scale
(click images to enlarge)
“On the engineering side of things we’ve … been very busy over the past year, and not to be outdone by the education team, we are ready to take the wraps off something special, this time aimed at business and industrial users,” writes James Adams, hardware director for the Raspberry Pi Foundation, in a blog post on the nonprofit organization’s website.
“From humble beginnings, the Raspberry Pi platform has grown and matured,” continues Adams. “The software is now full-featured and stable, and is still constantly improving thanks to the continuing hard work of our heroic community of volunteers; as well as targeted injections of funding to solve some specific issues. The Pi, and the Broadcom BCM2835 SoC at its heart, are also steadily becoming more open.”
Soul of a popular machine
Like the Raspberry Pi SBC it mimics, the 67.6 x 30mm, SODIMM-style Compute Module is based on a Broadcom BCM2835 system-on-chip accompanied by 512MB of RAM memory. In place of the SBC’s SD card, however, the COM’s bootloader and OS stack reside in a soldered-on 4GB eMMC flash chip.
Other than that, all SoC signals not consumed by on-board memory or other components are expressed on the card’s edgecard fingers, making them available to electronics on an application-specific baseboard. As a result of this approach, “many more GPIOs and interfaces are available as compared to the Raspberry Pi,” explains Adams. “Designing the module into a custom system should be relatively straightforward as we’ve put all the tricky bits onto the module itself.”
Raspberry Pi COM baseboard empty, and stuffed with Pi
(click images to enlarge)
As with all COMs, the Raspberry Pi Compute Module is supported by a companion baseboard — the open-source “Compute Module IO Board” — which is aimed at jump-starting software and hardware development using the COM. In addition to an SODIMM socket for the COM, the baseboard includes circuitry for programming the COM’s eMMC flash memory, and offers “friendly” access to the SoC’s interface signals via pin headers and flexi connectors,”much like the Pi,” adds Adams. It also provides real-world HDMI and USB connectors, making it possible for the COM and baseboard to immediately boot-up Raspbian “or the OS of your choice.”
While few details are enumerated at this point, key specs for the Raspberry Pi Compute Module appear to include:
- Processor — Broadcom BCM2835 SoC:
- CPU — 700MHz ARM11 core
- GPU — Broadcom VideoCore IV
- RAM — 512MB SDRAM
- Storage — 4GB eMMC flash
- Expansion interface — 200-pin SODIMM connector (custom wired)
- Dimensions — 67.6 x 30mm
Meanwhile, specs for the Compute Module IO Board appear to include:
- SODIMM socket for Compute Module
- Coastline I/O ports:
- 2x serial camera ports
- 2x serial display ports
- GPIO expansion — 120 header pins (2x 60-pin dual-row headers)
- Power — 5VDC input via microUSB conector
This short video introduces the Raspberry Pi Compute Module, and shows it booting its Raspbian OS:
“We love hearing about what users are doing with their Raspberry Pis, and are constantly amazed at the range of projects, as well as the inventiveness and creativeness of the community,” continues Adams in the blog post. “We are also aware that there are a very significant number of users out there who are embedding the Raspberry Pi into systems and even commercial products. We think there needs to be a better way to allow people to get their hands on this great technology in a more flexible form factor, but still keep things at a sensible price. Like proud parents, we want to free the core technology of the Raspberry Pi to go forth and become an integral part of new and exciting products and devices, and so today we are announcing the forthcoming Raspberry Pi Compute Module.”
The Raspberry Foundation is initially releasing schematics for both the Compute Module and the IO Board, but “will be adding plenty more documentation over the coming days and weeks,” writes Adams. “The Raspberry Pi Foundation is a charity, and as with everything we make here, all profits are pushed straight back into educating kids in computing.”
The Raspberry Pi Compute Module and IO Board will initially be offered as part of a Raspberry Pi Compute Module Development Kit, available from RS Components and Premier Farnell’s Element 14 “some time in June,” followed by availablilty of the COM separately. The COM will be priced around $30 in quantities of 100, and at a “slightly higher” price for single units, according to Adams.