self stater for JK flipflop UP/down counter

Thread Starter

flonchon

Joined Oct 8, 2015
5
Hello :), I have a JK UP/DOWN counter project to build.
my sequence is 1, 3, 5, 7, 12, 13, the count should start with 000 but after finish one cycle (from 1 to 13 for UP counting) the number 0 doesn't have to display anymore.
I did my karnaugh map, drawing and building. I self start at the number 1 to check if my sequence work, my DOWN counting work, and my UP counting also but I don't get it how to self start at 000. I did connect all my clear to my self starter but It doesn't work. Thank you...
20151015_231218.jpg 20151015_231255.jpg 20151015_231309.jpg
 

RBR1317

Joined Nov 13, 2010
512
Assuming that the RC circuit at the far right is the self-starter, how do you ensure that the 10 uF capacitor is fully discharged for startup? Does it completely discharge through the +Vcc terminal?
 

Thread Starter

flonchon

Joined Oct 8, 2015
5
yes the RC circuit is the self starter, our tutor told us to connect a 10 Kohms resistor and a 10 uF capacitor for our last project (up counting).
I didn't think about that thank you, is it mean I need a bigger capacitor value to completely discharge through the +Vcc terminal?
 

Thread Starter

flonchon

Joined Oct 8, 2015
5
I just tried with 10 uF it works up and down counting when I self start with any of my sequence number (1, or 3 or 5...etc).
Only when I self start at 0 (all preset to VCC and all clear to RC circuit), I have a problem with my down counting, it starts at 0 but after instead of have one of my down digit number, nothing display on my 7-segment and all my LED are ON, only after that it count normally.
 
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