The ClusterCTRL Single is a low-cost controllable USB Gadget carrier for the Raspberry Pi Compute Module. Breaking out 38 (non-power) GPIO so it's also useful where you need more than the 28 (non-power) GPIO pins accessible on the more regular 40 pin Raspberry Pi (A/B/A+/B+/Zero).

Uses

Raspberry Pi Cluster - With the ClusterCTRL software on a Raspberry Pi controller (or manual setup on Linux) the Single module (alone, with the ClusterHAT, Triple, or multiple Singles) can be controlled using the "clusterctrl" command - to power on/off, turn usbboot on/off, save defaults etc. Compute modules can be booted from the onboard eMMC (if available) or as a USB device on all models.

Can be used to write images to Compute Modules with onboard eMMC.

Once software has been uploaded to the Compute Modules onboard eMMC it can be used standalone (disable USBBOOT).

Breakout Interfaces

On the top of the carrier the function names (or BCM number) are printed, the bottom shows the BCM GPIO number. Numbers are shown in brackets where you need to bridge a solder jumper on the bottom of the PCB to connect the GPIO to the pin, for example BCM 21 on the UART0 header where it would conflict with the 3v3 pin on many serial adaptors.

The following pins can be accessed after soldering on standard 0.1" pitch headers, they're grouped into sections (but can be used as standard GPIO or other ALT functions).

* Using BCM GPIO numbering

** Only one UART interface can be used with hardware flow control (see the documentation).

There are also a headers for.

• The 3.3v and 1.8v power rails (GPIO pins use 3.3v logic)
• A power jumper to use both power and data over the connector labelled "USB", ideal when using a powered USB HUB.
• 6-pin PGN header to reprogram the AVR controller (uses our open source software).

USB connectivity

The ClusterCTRL Single can be used standalone (you can set the default power and boot settings with the clusterctrl tool) or as a USB Device (USB OTG Gadget Serial/Network/etc).

The micro USB port cannot be used to plug in USB storage, Webcam etc. as there's a USB hub in-between.