W
Wouter van Ooijen
- Jan 1, 1970
- 0
I am confused about the edge on which a FF triggers. My intuition
would say that any logic symbol with a plain wedgie (no inverting
blob) should trigger on the positive edge, but maybe that's too
simple.
H&H 2nd edition P508/509 states that a JK triggers on the negative
edge, and an edge-triggered FF on the positive edge. But it is not
clear whether that refers to the implementation as shown, or to thje
bare logic symbol. Most JK symbols do have the inverting blob on the
clock input.
P510 suggests that both dividers behave the same, which would imply
that the plain JK symbol triggers on the negative edge,
Yet P511 states that the shown ripple divider clocks on the negative
edge, the JK symbols do have the inverting blob, so the plain JK
symbol would clock on the positive edge.
My tenative conclusion is that a plain (no inverting blob) D FF clocks
on the positive edge. But on which edge clocks a plain JK FF?
Positive, neative, or worse: there is no standard?
Wouter van Ooijen
-- ------------------------------------
http://www.voti.nl
PICmicro chips, programmers, consulting
would say that any logic symbol with a plain wedgie (no inverting
blob) should trigger on the positive edge, but maybe that's too
simple.
H&H 2nd edition P508/509 states that a JK triggers on the negative
edge, and an edge-triggered FF on the positive edge. But it is not
clear whether that refers to the implementation as shown, or to thje
bare logic symbol. Most JK symbols do have the inverting blob on the
clock input.
P510 suggests that both dividers behave the same, which would imply
that the plain JK symbol triggers on the negative edge,
Yet P511 states that the shown ripple divider clocks on the negative
edge, the JK symbols do have the inverting blob, so the plain JK
symbol would clock on the positive edge.
My tenative conclusion is that a plain (no inverting blob) D FF clocks
on the positive edge. But on which edge clocks a plain JK FF?
Positive, neative, or worse: there is no standard?
Wouter van Ooijen
-- ------------------------------------
http://www.voti.nl
PICmicro chips, programmers, consulting