Raspberry Pi Compute Module 3 (CM3) and Compute Module 3 Lite (CM3L) Datasheet Released

Last week NEC announced they were going to use Raspberry Pi Compute 3 Module in some of their presentation and digital signage displays. This led to a longish discussion in the blog post, during which one commenter left a link to Raspberry Pi Compute Module 3 datasheet, so let’s have a look.

Raspberry Pi 3 Compute Module Block Diagram (Click to Enlarge)
Raspberry Pi 3 Compute Module Block Diagram (Click to Enlarge)

There will actually be two version of the Broadcom BCM2837 based Compute Module with CM3 with a 4GB eMMC, and CM3 Lite (CM3L) without eMMC, but SD card signal are available to the baseboard. Apart from storage differences, both modules shared the same specifications:

  • SoC – Broadcom BCM2837 quad core Cortex A53 processor @ 1.2 GHz with Videocore IV GPU
  • System Memory – 1GB LPDDR2
  • Storage
    • CM3 Lite – SD card signals through SO-DIMM connector
    • CM3 – 4GB eMMC flash
  • 200-pin edge connector with:
    • 48x GPIO
    • 2x I2C, 2x SPI, 2x UART
    • 2x SD/SDIO, 1x NAND interface (SMI)
    • 1x HDMI 1.3a
    • 1x USB 2.0 HOST/OTG
    • 1x DPI (Parallel RGB Display)
    • 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)
  • Power Supply – VBAT (2.5V to 5.0V) for BCM2837 processor core, 3.3V for PHYs, UI and eMMC flash, 1.8V for PHYs, IO, and SDRAM, VDAC (2.8V typ.) for video composite DAC, GPIO0-27_VREF & GPIO28-45_VREF (1.8 to 3.3V) for the two GPIO banks.
  • Dimensions – 67.6 x 31 mm; compliant with JEDEC MO-224 mechanical specification used in DDR2 SO-DIMM memory module
  • Temperature Range – -25 to +80 degrees Celsius

Compute Module 3 and 3 Lite are basically mechanically & electrically compatible with the original Raspberry Pi Compute Module (CM1), so if you have an existing design based CM1, CM3 should be a drop-in replacement, bearing in mind the following differences explained in the datasheet:

Apart from the CPU upgrade and increase in RAM the other significant hardware differences to be aware of are that CM3 has grown from 30mm to 31mm in height, the VBAT supply can now draw significantly more power under heavy CPU load, and the HDMI HPD N 1V8 (GPIO46 1V8 on CM1) and EMMC EN N 1V8 (GPIO47 1V8 on CM1) are now driven from an IO expander rather than the processor. If a designer of a CM1 product has a suitably specified VBAT, can accommodate the extra 1mm module height increase and has followed the design rules with respect to GPIO46 1V8 and GPIO47 1V8 then a CM3 should work fine in a board designed for a CM1.

The datasheet also includes detailed mechanical and electrical specifications necessary to build a baseboard for the Compute Module.

CM3 and CM3L Mechanical Dimensions
CM3 and CM3L Mechanical Dimensions

It should also be enough for people to design a compatible SoM based another processor, but so far I’m not aware of anybody having done so with Compute Module 1.

Raspberry Pi Trading guarantees availability of CM1, CM3 and CM3 Lite until at least January 2023.

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5 Replies to “Raspberry Pi Compute Module 3 (CM3) and Compute Module 3 Lite (CM3L) Datasheet Released”

  1. “Raspberry Pi Trading guarantees availability of CM1, CM3 and CM3 Lite until at least January 2023.”

    How is it “guaranteed”? Is there financial compensation if they can not meet that goal?

    More likely it should say “Pi Trading would like availability until Jan 2023”. Broadcom has already been sold off and their mobile division disbanded. Furthermore, there are already supply issues with their current products as noted repeatedly on their forums. A seven year “guarantee” is very much just wishful thinking in my opinion.

  2. Were/are there any products available based on CM1 apart from the Slice media player (founded by RPi fellows) and the OTTO camera (made by Next Thing Co — it seems they were so overwhelmed that their next thing was the C.H.I.P. and now they target the same market with their C.H.I.P. Pro)

  3. There was a comment made in the office to the effect of “they are guaranteeing they will rip Pi3s from the hands of needy children to ensure their corporate customers have adequate supply”. While a bit over the top, it does illustrate the conflict of interests Pi Trading has with the Foundation goals.

  4. RS only sold 3715 units of the CM1 over the all of the past year (you can check historic stock levels via the web archive) and demand has been tapering off so I guess if they made 10000 and stash them somewhere safe it’s good until 2023.

    In comparison Raspberry Pi sold 100.000 on first day

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