I'm not quite sure what it is that you're trying to do. Even if you don't
want to use an input signal to specify when to reset, .clr is still the
extension you want. For example:
WHEN (some logical expression is 1) THEN
flipFlopName.clr = 1;
Try and stick to the .extensions I've specified. The others can lead you
into all sorts of trouble and you shouldn't need them for this class.
> On Mon, 10 Mar 1997, Matt Lease wrote:
> > > When I am trying to do my mode selector, I try to use the flip-flops
> > > provided by the ABEL (istype 'reg, buffer';) However, when I am doing
> > > that, I have no idea how can I set the initial value for that signal. I
> > > try the .PR, .SP and something like that and I still get the undefined
> > > signal. Is there any ways to do the preset with the provided flip-flops
> > > in the ABEL?
> > Here is a pretty complete description of using flip-flops in ABEL:
> > instantiation: "istype 'reg, buffer'"
> > assignment: "flipFlopName := VALUE"
> > synchonous reset: "flipFlopName.clr = rst", where "rst" is your input pin
> > that indicates when you want to reset to 0
> > synchonous set: "flipFlopName.set = set", where "set" is you input pin
> > that indicates when you want to set the value to 1
> > Use the synchonous output in your calculations (ie check what your current
> > state is if you have a flip-flops representing your FSM's current state)
> > : somePin = flipFlopName.fb;
> > .clr, .set, and .fb should be the only .extensions you use
> > You should not say: "somepin = flipFlopName", as this is ambiguous whether
> > you want the synchronous or asynchonous output of the flip-flop. Always
> > use the .fb extension to specifiy the synchonous output.
> > HOpe this helps. Any questions? Let me know.
> > matt