the order in which some switches are turned on
in [FPGA]
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From: backhus on 23 Apr 2008 02:09 Hi Laura, FPGAs can do what you want, though it might be simpler do solve with a microcontroller. The tricky thing is to define "in the same moment" more technically. If the switches are operated manually it is virtually impossible to have two switches changing their state "in the same moment", even if they are mechanically coupled. The mechanical parts have their tolerances and that leads to some micro-nano-whatsoever seconds of difference. The question is: How precise do you want to detect the states of the switches and determine changes. Furthermore, even if you choose a low time resolution the asynchronous incoming events of 2 switches may happen around the moment of sampling the states of the switches. So you get two events instead of the expected/desired single one. The rest is a simple act of storing, and transmitting/displaying the information. That's just depends on your hardware. In general: Your requirements are too loose. Be more specific. What means "must be simple to read" A bunch of lamps would do it, but then: "by a human, computer, etc" Humans and computers barely read the same things easily (e.g printout vs. RS232). And who is etc? ET's-Companion? :-) Anyway, wether you choose FPGAs or microcontroller to solve the problem you have to make a decision about the way the device shall interact with the rest of the world, and then just do it. (Which means write some code to describe the hardware or program a processor or both ) Have a nice synthesis Eilert laura schrieb: > Hi all, > > > I have an array of N switches . Initially all are OFF. > > > Somebody turns them ON in some order. It is possible that more > switches are turned ON in the same moment. > > > I need a device which shows me the order in which the switches were > turned ON. For instance the device should give me: 4,3,1,5,2 (this is > the order in which the switches were turned ON). > > > The way in which the output is shown in not important. It must be > simple to read (by a human, computer, etc). > > > It is important that the device is able to handle the turned ON (in > the same moment) of the multiple switches. > > > thanks, > Laura >
From: jkljljklk on 24 Apr 2008 17:02
On Apr 23, 1:21 am, laura <laura.brandu...(a)gmail.com> wrote: > Hi all, > > I have an array of N switches . Initially all are OFF. > > Somebody turns them ON in some order. It is possible that more > switches are turned ON in the same moment. > > I need a device which shows me the order in which the switches were > turned ON. For instance the device should give me: 4,3,1,5,2 (this is > the order in which the switches were turned ON). > > The way in which the output is shown in not important. It must be > simple to read (by a human, computer, etc). > > It is important that the device is able to handle the turned ON (in > the same moment) of the multiple switches. > > thanks, > Laura You can create a process that will be triggered by a clock. The faster this clock is, more accurate your timing will be - ie not more then one switch will be turned on for one clock cycle. At every clock event all the switches are read, and if one of them is turned on, its value is written by this process to some array that will give you the order of the switches. Hope this help. Dan |