New Raspberry Pi Compute Module 3+: Here's what you need to know

The Raspberry Pi Compute Module 3+ is designed as a drop-in replacement for the existing Raspberry Pi Compute Module 3.

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Firms looking to build the low-cost Raspberry Pi computer into products can now buy the Raspberry Pi Compute Module 3+, which runs cooler and offers more storage than its predecessors.

The Raspberry Pi Compute Module 3+ (CM3+), revealed today by Raspberry Pi Trading, is designed as a drop-in replacement for the existing Raspberry Pi Compute Module 3.

Unlike the typical Raspberry Pi Model A and B boards, the Raspberry Pi compute modules are not designed to be used as a home computer, but are slimmer and thinner boards designed to sit inside industrial and consumer appliances.

The Compute Module 3+'s improvements over the Compute Module 3 mean its CPU can sustain its performance for longer periods when under heavy load, says James Adams, COO of Raspberry Pi Trading.

"The CM3+ has better thermal behaviour under load. It has more thermal mass and can draw heat away from the processor faster than CM3," he says, explaining this improved heat spreading means either lower average temperatures or that it takes longer for the CPU to hit 80C and begin reducing its operating speed. The rated ambient temperature range for the CM3+ is also wider, ranging from -20°C to 70°C.

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Despite using the same underlying BCM2837B0 system-on-a-chip (SoC) as the Raspberry Pi 3 Model B+, the CM3+ still shares the CM3's 1.2GHz CPU clock speed, a decision Adams says was due to power supply limitations.

The CM3+ also increases the maximum onboard storage, from the 4GB eMMC storage on the Compute Module 3. Instead, the CM3+ is available with a choice of no eMMC storage ($25), 8GB eMMC storage ($30), 16GB eMMC storage ($35), 32GB eMMC storage ($40). The no eMMC storage option, known as CM3+ Lite, brings the SD card interface to the module pins, allowing the user to add an eMMC or SD card of their choice.

Adding more flash memory to the Raspberry Pi Compute Module was "one of the most frequent requests from users and customers", according to Adams.

Adams says the CM3+'s price was designed to be affordable to even the smallest outfits that want to build a product around the board.

"We limit the price so that the "maker in a shed" is not disadvantaged when producing only a few hundred products relative to professionals with much larger production runs," he says.

"The Compute Module takes care of the high-tech bits (fine-pitched BGAs, high-speed memory interfaces, and core power supply), allowing the designer to focus on the differentiating features they really care about."

Like its predecessors, the CM3+ is the same size as a DDR2 small outline dual in-line memory module, and is a flat board, as it lacks the populated ports, the bulky USB and HDMI connectors found on the traditional Pi boards.

All of these interfaces are still available on the CM3+, but like earlier CM boards, the CM3+ plugs into a user-created carrier board, via a standard 200-pin DDR2 SODIMM connector, and it is up to the user which ports they chose to expose.

The Compute Module boards also provide more interfaces than the regular Raspberry Pi, supporting two cameras and two displays, as well as extra GPIO (general purpose input-output).

The only change in dimensions in the CM3+ is a very slight increase to the height of the board over the CM3.

The CM3+ is the third Compute Module board, after the earlier CM3 and original Raspberry Pi Compute Module. The boards have been used inside various IoT, home and factory automation products — including NEC digital signs and the industrial-grade Revolution Pi from Kunbus.

Raspberry Pi Trading is also releasing a Compute Module 3+ Development Kit today. This kit contains 1 x Lite and 1 x 32GB CM3+ module, a Compute Module IO board, camera and display adapters, jumper wires, and a programming cable.

As of publication, the CM3+ was listed as available via Mod My Pi in the UK and Newark element 14 in the US.


The Raspberry Pi Compute Module 3 .

Image: Raspberry Pi Trading

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