Hi Yes, but look at all the Danish lawyers that earn a living by going after just such stupidity ....
Bob On Feb 17, 2010, at 7:33 PM, Bruce Griffiths wrote: > Yet another reason to use an operating system that doesn't enforce such > arcane requirements intended as part of an insidious content protection > systems that prevent one from acquiring ones own data. > > Bruce > > Bob Camp wrote: >> Hi >> >> No Windows 7 driver signing issues with a serial port. USB can be a bit of a >> tangle that way, not as easy as it used to be. >> >> Bob >> >> >> On Feb 17, 2010, at 7:20 PM, Bruce Griffiths wrote: >> >> >>> Lux, Jim (337C) wrote: >>> >>>>>> I don't know if there's a FIFO in front of the UART (e.g. what if you >>>>>> get simultaneous zero >>>>>> >>>>>> >>>>> crossings).. but I would expect there is. >>>>> >>>>> >>>>>> The "hard work" is in the zero crossing detector ahead of the FPGA. (and >>>>>> perhaps in the latching of >>>>>> >>>>>> >>>>> the ZCD inputs into the FPGA). >>>>> >>>>> >>>>>> Given how long ago it was made, that FPGA isn't a huge one. >>>>>> >>>>>> >>>>>> >>>>>> >>>>> Using 8 flag bits (one per channel) together with the associated time >>>>> stamp is a little more efficient and very easy to do and it doesn't >>>>> require a FIFO to ensure that simultaneous zero crossings aren't missed. >>>>> >>>>> >>>>> >>>> Still need the FIFO.. >>>> Say you got one zero crossing at 0x01000 and the next at 0x01001 (where >>>> the number is the 20 bits in hex).. you'd still be sending the characters >>>> out the UART for the 0x01000 crossing when the next crossing occurred 10ns >>>> later. >>>> >>>> If I were doing it today (and I have no idea how Steve built it 10 years >>>> ago), I'd do something like a character for channel number and direction >>>> (ascii 0 through 7 for positive going, 8 through F for negative going) and >>>> 5 characters for the count (in hex), followed by a carriage return. All >>>> printable characters, easy for testing, no hiccups with DOS or some device >>>> driver trying to interpret binary, etc. >>>> >>>> You've got 8 channels, each zerocrossing at about 200-300 Hz (the >>>> difference frequency is 123 or 124 Hz, so you get twice that many zero >>>> crossings), or about 1600-2400 messages/second. At 6 characters per >>>> message, that's about 10,000 characters per second, so you'd need a fairly >>>> fast UART to keep up. (OTOH, the article mentions dropping characters..) >>>> >>>> They might have only used one direction of zero crossing, which gets you >>>> down to the 5000 characters per second, which you might be able to squeeze >>>> into a 38.4kbps serial stream, especially if you go to a denser packing. >>>> But you'll still need a FIFO. >>>> >>>> Next time I see one of the FTL guys, I'll ask. >>>> >>>> Jim >>>> >>>> >>>> >>> A LAN, USB or Firewire interface may be more appropriate all are easy to >>> implement. >>> >>> Bruce >>> >>> >>> _______________________________________________ >>> time-nuts mailing list -- time-nuts@febo.com >>> To unsubscribe, go to >>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>> and follow the instructions there. >>> >>> >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts@febo.com >> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> >> > > > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
