After all my noise about the FT232R polling at 125 microseconds, I thought I would see if I could make a hanging bridge. To my surprise and annoyance, it was polling at 1ms.
I screwed around for a while but couldn't get it to work on the hardware and kernel that it was plugged into. I think there is a magic mux between the USB hardware/firmware on the host and the wires to the connectors. If I plug a thumb drive into a connector, I get a different USB hub than I get when I plug a GPS mouse into the same connector. After a while, I tried it in a newer system. That polls at 125 microseconds. Well, most of the time. Every 5 min (rough) it gets another 125 microseconds added to the timing. Here are a couple of graphs. http://users.megapathdsl.net/~hmurray/time-nuts/USB/USB-125usec-a.png http://users.megapathdsl.net/~hmurray/time-nuts/USB/USB-125usec-b.png Does anybody know anything about this quirk? Initially, I had another GPS gizmo plugged into that box. Now there there are no other USB devices. Bus 002 Device 002: ID 8087:0024 Intel Corp. Integrated Rate Matching Hub Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Bus 001 Device 004: ID 0403:6001 Future Technology Devices International, Ltd FT232 Serial (UART) IC Bus 001 Device 002: ID 8087:0024 Intel Corp. Integrated Rate Matching Hub Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Bus 004 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub Bus 003 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub -- These are my opinions. I hate spam. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
