- Controllerless - all three Compute Modules are USB Devices (USB Gadget Ethernet/Serial/etc).
- Boot from Compute Module eMMC (if available) or via rpiboot (software selectable).
- All models of Compute Module can be used (CM1/CM3/CM3+ with/without eMMC).
- Can be used with a Raspberry Pi Controller (or other Linux machine).
- Multiple ClusterCTRL devices can be used on the same controller.
- ClusterCTRL (I2C) USB interface allows individual control of Pi power, fan, LED, etc.
- Programmable power on states for LED, Individual Pi Power, USBBOOT, etc.
- Unpopulated pads for ClusterCTRL UART status (for debug)
- Works with the standard Cluster HAT software or you can roll your own.
- Power for the compute modules is provided by a dedicated micro USB connector.
The Cluster Triple is controllerless meaning all three compute modules are nodes (none of them are the controller) so it must be used with another computer (normally a Pi) to route/bridge the USB Gadget Ethernet/Serial and control the power. This is setup automatically when using the Cluster HAT controller images (based on Raspbian) on a Raspberry Pi.
The ClusterCTRL Triple controller uses our open source firmware(building on i2c_tiny_usb which uses V-USB) running on a Microchip ATMEGA328P/PB to provide a standard I2C interface for controlling the cluster from a controller Pi.
The Compute Modules boot method can be selected via the controller.
- With USBBOOT enabled (or CM without eMMC) the Compute Module presents as a USB device allowing rpiboot to boot the full Linux system (this is handled automatically with the ClusterCTRL images) or as a Mass Storage Device allowing the onboard eMMC to be written.
- On a Pi without eMMC USBBOOT can be disabled allowing the Compute Module to boot from it's onboard eMMC.
On the top of the ClusterCTRL Triple there's a 2 pin header for software controlled a 5v fan.
The underside of the ClusterCTRL Triple has 4 (unpopulated) UART connectors (6-way SMD 0.1" pitch header), one for each Compute Module (UART0) and another for serial debug output of the Controller (not enabled by default).
The 5V power voltage can also be read via the controller with clusterctrl status.
The USB controller uses the Linux i2c_tiny_usb driver, allowing the functions to be contrlled via I2C.
The following are not provided with the ClusterCTRL Triple but are required.
- Micro USB power supply (2.5A).
- One to Three compute modules, any mix of CM1/CM3/CM3+ (Lite/4GB/8GB/16GB/32GB)
- A controller (this is normally a Raspberry Pi running the Cluster HAT controller software).