Need help with some problem here.

[qlouis76]

Hi,

I am facing some problem here.. There must be a sequance of number come out (4,7,2,5,0,3,6,1) after the circuit is done.

But I am facing problem with the 7447 and the seven segment. 

Here are the component I use. Using 7490, 74HC04N x3, 74LS08N x5, 74LS32N x3, 74LS47N, LM555CM and Seven segment display.

Pls help.. Below are the attachment of multisim. Pls check the circuit is right or wrong. 

Don't have much knowladge for digital. First semester of E&E 

Thank you. 

[Tom__Sedlack]

The little circles on the LT, RBI, and BI/RBO inputs signify that those functions are active low which means a logic low on the pin causes the function to be used.  You have all of them active when none of them should be. Also, it is good practice to terminate all input pins either high or low.  In the simulator, when a pin is left open, it will default to logic low.  In the real world, an open pin is undetermined (can float high or low) unless the spec sheet for the part says otherwise.

[qlouis76]

Thank you for the reply. Can help me to make the little changes that i make mistake? 

Here are the lateast one I have with 555 timer... When I switch on, it stuck at 4.. 

Pls help..

Thank you. 

[Tom__Sedlack]

There is something going on with the timer circuit. Your entered values should give you a 1 Hz square wave at ~52% duty cycle but the simulation stops after a few milliseconds of simulation time.  I don't think MS is good with timers and I don't use them when I am simulating a circuit.  I removed the 555 circuit and replaced it with the function generator and your circuit works as intended. Maybe somebodu else can help out eith suggestions for the timer.  

[qlouis76]

Thank you for the help... But I am working on the 555 timer actually... Do you know why the timer will stuck after a few ms? 

Thank you for the help. =] 

Regards

Louis