Compute Module Datasheet

Copyright Raspberry Pi (Trading) Ltd. 2016

9.1.4

SD/SDIO Interface

The BCM283x supports two SD card interfaces, SD0 and SD1.

The first (SD0) is a proprietary Broadcom controller that does not support SDIO and is the primary

interface used to boot and talk to the eMMC or SDX x signals.

The second interface (SD1) is standards compliant and can interface to SD, SDIO and eMMC devices;

for example on a Raspberry Pi 3 it is used to talk to the on-board BCM43438 WiFi device in SDIO

mode.

Both interfaces can support speeds up to 50MHz single ended (SD High Speed Mode).

9.2

CSI (MIPI Serial Camera)

Currently the CSI interface is not openly documented and only CSI camera sensors supported by the

official Raspberry Pi firmware will work with this interface. Supported sensors are the OmniVision

OV5647 and Sony IMX219.

It is recommended to attach other cameras via USB.

9.3

DSI (MIPI Serial Display)

Currently the DSI interface is not openly documented and only DSI displays supported by the official

Raspberry Pi firmware will work with this interface.

Displays can also be added via the parallel DPI interface which is available as a GPIO alternate function

- see Table 9 and Section 9.1.3

9.4

USB

The BCM283x USB port is On-The-Go (OTG) capable. If using either as a fixed slave or fixed master,

please tie the USB OTGID pin to ground.

The USB port (Pins USB DP and USB DM) must be routed as 90 ohm differential PCB traces.

Note that the port is capable of being used as a true OTG port however there is no official documentation.

Some users have had success making this work.

9.5

HDMI

BCM283x supports HDMI V1.3a.

It is recommended that users follow a similar arrangement to the Compute Module IO Board circuitry

for HDMI output.

The HDMI CK P/N (clock) and D0-D2 P/N (data) pins must each be routed as matched length 100

ohm differential PCB traces. It is also important to make sure that each differential pair is closely phase

matched. Finally, keep HDMI traces well away from other noise sources and as short as possible.

Failure to observe these design rules is likely to result in EMC failure.

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