DFF

[JustinM]

I understand that DFFs can't be built in the simulator, and have been implemented as a primitive, but I would like to understand how they work. Does anyone have a schematic of how they are built in the real world?

[ybakos]

http://www.play-hookey.com/digital/sequential/

And read Code by Charles Petzold for a gentle introduction.

[JustinM]

Wow... I just found this...
http://www.marksmath.com/tecs/dff/dff1.html

Did you actually build a DFF in the Hardware Simulator Mark? Nothing is impossible for you, huh? :D

[JustinM]

Thanks ybakos... I actually just ordered Code on Friday... it should be delivered tomorrow... woohoo!!

[cadet1620]

Best online resource to learn DFFs is http://www.play-hookey.com/digital/sequential/

A really good schematic based logic simulator that can handle sequential circuits is Logisim.

My DFF in the Hardware Simulator would best be called a meta-DFF. It's built out of clocked Nand gates, and uses the Hardware Simulator as a logic analyzer to show what happens as inputs, including the clock, change.

--Mark

[JustinM]

Thanks everyone. I'll study up on this tonight.

[JustinM]

I've been reading CODE and when I got to page 171 I thought, "Say, I wonder if this can be done in the TECS simulator?" Then I remembered this post... Low and behold you built the same edge triggered D-type flip-flop in the TECS simulator! How neat!

I need to start clocking in my TECS time every day again. It's been put aside but I'm definitely coming back to it. Hopefully reading CODE compensates a little. :)