FireWire

From MythTV Official Wiki
Revision as of 04:58, 20 February 2006 by YLee (talk | contribs)

Jump to: navigation, search

FireWire (also known as i.Link or IEEE 1394) is a personal computer and digital video serial bus interface standard offering high-speed communications and isochronous real-time data services. FireWire can be considered a successor technology to the obsolescent SCSI Parallel Interface. Up to 63 devices can be daisy-chained to one FireWire port.

FireWire works very well in connecting a MythTV backend to certain cable boxes (including the Motorola DCT-6200). MythTV 0.18 and up contains built-in support for changing channels on the DCT-6200 (generally reliable, although occasionally digits get dropped). How to get started:

  • Figure out what node the FireWire is connected to. 'plugreport' will typically show a single FireWire connection on Node 2. Two FireWire connections typically appear on Nodes 0 and 3. However, these will often vary randomly after the cable box and/or the backend restarts.
  • Either Point-to-Point or Broadcast works well with a single FireWire connection. Do not set two simultaneous connections to Broadcast; at least one should be set to Point-to-Point.
  • 200Mbps is the recommended connection speed.
  • If 'Firewire: No Input in 15 seconds' appears in mythbackend.log, try the following shell script:
#!/bin/sh

# This script assumes that two FireWire connections are on
# Nodes 0 and 3, both are set to 200Mbps, Node 0 is set to
# Broadcast, and Node 3 is set to Point-to-Point.

plugctl -n 0 oPCR[0].data_rate=2
plugctl -n 0 oPCR[0].n_p2p_connections=0
plugctl -n 0 oPCR[0].bcast_channel=63
plugctl -n 0 oPCR[0].bcast_connection=1

plugctl -n 3 oPCR[0].data_rate=2
plugctl -n 3 oPCR[0].n_p2p_connections=1
plugctl -n 3 oPCR[0].bcast_channel=0
plugctl -n 3 oPCR[0].bcast_connection=0