Can Power Raspberry Pi via microUSB from a hub port, plus three more devices. USB Audio peripheral tested and working. No back-voltage on upstream connection. This is accomplished by removing a jumper on the Printrboard called «BOOT». Firmware can only be loaded while the chip has booted into its bootloader. Geeetech is one supplier selling the 2-layer boards. (This no longer appears to be true.) There may be others. Does work with Windows and comes with a beefy 3,5 A power supply that works with a Belkin 7-port mobile USB-Hub to power a cluster of 4 Raspberries. All extra I/O ports of the AT90USB have been broken out to headers for prototyping and expansion.
Since Pi can’t benefit from USB 3.0, better off to use one of the Plugable USB 2.0 7 or 4 port hubs like USB2-HUB-AG7 to both power the Pi and attached USB devices. Lowest cost and greatest performance of all RepRap motherboards at time of release, March 2012. Software All preassembled Printrboards come pre-loaded with a bootloader and firmware. Obtain a compiled bootloader (CDC, HID, or DFU). See Lincomatic’s Bootloaders for AT90USB1286 article for pre-compiled copies of each bootloader. LogiLink USB 3.0 Hub 4-Port with 2A Power Supply. 2109:2811. Detectes and crashes during boot. mmc0: Timeout waiting for hardware interrupt, mmcblk0: error -110 sending status command, cannot find and mount root, kernel panic.nGear nGear G-H508 Mini 4 Port USB2.0 Hub. Thermistors Thermistor headers are 2-pin Molex headers at the right side of the board, located above the reset button.
The Pi Hut Trendnet  TU2-700 7 Port Powered USB 2.0 Hub with AC Adapter (5 V 2 A) Tripp-Lite  U222-007-R 7 Port Powered USB 2.0 Hub with AC Adapter (5 V 2.5 A) Powering Raspberry Pi from the hub works. When this is done the ports do not provide any power. I assume this is caused by the reset logik that turns of power when an usb reset is given. The specification also requires that such low-power devices have a minimum operating voltage of 4.4 V, which means that even with the 0.4 V diode drop the hub will supply sufficient voltage. Fuses for the factory DFU bootloader should be set as avrdude -c usbtiny -p at90usb1286 -U lfuse:w:0x5E:m -U hfuse:w:0x99:m -U efuse:w:0xF3:m Loading Firmware (Windows) To load new firmware to your Printrboard, first determine which bootloader your board uses. CDC or DFU are most likely. Трансформатор входит в комплект d75 h60 D90 H30 LED 7Вт cоответствует 70Вт лампе накаливания. Assuming the voltage is now in the 100 mV range, the voltage drop across the diode is very nearly 5 V and Ohm’s law gives the current through the resistor in the 1 µA range.