Mac Pro Computers (January 2008)
The Mac Pro computers with Quad-Core Intel Xeon 5400 Series microprocessors were introduced in January 2008. The Mac Pro provides two FireWire 800 IEEE 1394b ports and two FireWire 400 IEEE 1394a ports. The four FireWire ports are on the same FireWire bus and share a single 12V DC-regulated power supply that can provide 18 W per port, for up to 28 W total. If a device is added that exceeds the power limit, the port will be disabled but the other ports will continue to function. Unplug the device, and the disabled port will recover in a short amount of time. FireWire port power is provided when the computer is on, in sleep, or off.
The Open Host Controller Interface (OHCI) connects to the South Bridge IC via a PCI Express 1-lane 2.5 GHz bus. The front and rear FireWire PHYs interface via the OHCI.
The Mac Pro provides front and rear port repeating when the computer is powered on or asleep. Front and rear repeating is also available when the computer is off, unless the computer was shut down from Mac OS X with no FireWire devices connected.
Mac Pro Computers (August 2006 and April 2007)
The quad-core Mac Pro was introduced in August 2006 and the 8-core Mac Pro was introduced in April 2007 as a configure-to-order-option. The Mac Pro provides two FireWire 800 IEEE 1394b ports and two FireWire 400 IEEE 1394a ports. The four FireWire ports are on the same FireWire bus and share a single power supply that can provide 7 W per port, up to 28 watts total. The FireWire 800 and FireWire 400 ports provide a regulated power of approximately 12 VDC.
The Open Host Controller Interface (OHCI) connects to the South Bridge IC via a 33 MHz PCI bus. The front and rear FireWire PHYs interface via the OHCI.
The Mac Pro provides front and rear port repeating when the computer is powered on or asleep. Front and rear repeating is also available when the computer is off, unless the computer was shut down from Mac OS X with no FireWire devices connected.
