Jean-Yves F. Barbier ha scritto: > The regular way to do it is to have the projector correctly adjusted to its > nominal speed(s) by regularly sending it to a specialist. > However, it is very easy to get a square signal from the projector, integrate > it, and make an sound lock loop (through a PLL, exactly alike radio frequency > generators), the only parameter added is: what is my non-audible timing speed > I can use to vary sound, so people won't ear the drift catch; this has a > specific > name in PLL but I didn't touch it for years, so I don't remember it. > At which frequency this square wave runs? The PLL seems too much for this... (see later) >>>> Many years ago, in the time of i386 machines, I programmed a similar >>>> thing under DOS with PowerBasic, but as far as I remember, I never found >>>> an easy way of reading the impulses, and of course I missed an app for >>>> >>> Use the parallel port, or on some machines (if it already exists) the swi >>> switch/connector. >>> >> Good idea :-) But which switch/connector do you mean? >> > > I don't know it it already exists but there was such a connector (at least; > sometimes > a physical switch) that raises an SWI (SoftWare Interrupt), this way you just > have to > have a small launcher @ SWI address to interract [well, that's not so easy, > because > usually SWI also need an 8 bits address present on the bus @ SWI trigger > time]. > You have to make research because this info comes from quite a bit of time > ago. > > The other way is to build a special addon card with an embedded DSP, which > will be > able to solve all @ once (but at a cost that is non-trivial.) > > JY > The ISA bus was very easy to operate, and there was also a pin which raised INT3 (debug interrupt); anyway, it was easy to grab any other interrupt. The PCI bus is very complicated instead. But... could'nt it work to use some USB adapter, perhaps a USB-to-parallel (5V interface, it has an ACK interrupt) or an USB-to-serial (it has interrupt too, for modem line change). Last resort, he he he..., use a USB mouse for the normal work, and a fake mouse in the PS/2 port (several switches: left button, right, middle and others, wheel). This last solution is not fast enough, perhaps - the system talks to the mouse with a serial interface. But probably, with added hardware (a small CPU), this last way is still more simple than going with the PCI bus. At least, there is no need to open the case... the CPU can count pulses very quickly (in real real-time), and pass to the computer some data more easy to manage.
Thinking over, surely there are around USB adapters for general IO. Surely you can find PCI cards. May be, though, that those equipment does not have drivers for linux. I imagine: OCX for visual basic, DLL for visual C, and this should be enough for the world... Regards, Doriano ------------------------------------------------------------------------------ Let Crystal Reports handle the reporting - Free Crystal Reports 2008 30-Day trial. Simplify your report design, integration and deployment - and focus on what you do best, core application coding. Discover what's new with Crystal Reports now. http://p.sf.net/sfu/bobj-july _______________________________________________ Gambas-user mailing list Gambas-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/gambas-user
