Im working on a traffic light simulation, and we are suddenly tasked to add a 7 segment.
We used a 74192 decade counter and I am finding it hard to find the necesary connections for the 74192 to a 7448 or 7447 7 segment decoder.

halp pls im toasted

 

I don't understand. You got four bits. You connect A to A, B to B, C to C and D to D. Where is the confusion?

 

The outputs of the 74192 are labelled Qa,Qb, Qc, Qd, just connect them to inputs A,B,C,D, OR 1,2,4,8, on the decoder driver,

where is the difficulty?

 

ive tried that, connecting QA - QD to input A - D
the output is just a steady HI State
hence when connected to the 7 segment, all LED are on (8)

 

Which decoder is it,whats the voltage state of the inputs to the decoder, high or low, and how have you connected the Lamp test pin?

 

First, do you have a schematic?

One possibility, how is pin 3 on the 7447 wired?

Second, can you check the outputs of the 74192? ABCD should be 1000b. If all the outputs (Qa, Qb, Qc, & Qd) are high, none of the segments should be lit. Here is the datasheet for the 7447/7448

How are the data lines wired on the 74192 (those marked ABCD)? What is the LOAD pin connected to...

Finally, do you have a schematic?

 

First, do you have a schematic?

One possibility, how is pin 3 on the 7447 wired?

Second, can you check the outputs of the 74192? ABCD should be 1000b. If all the outputs (Qa, Qb, Qc, & Qd) are high, none of the segments should be lit. Here is the datasheet for the 7447/7448

How are the data lines wired on the 74192 (those marked ABCD)? What is the LOAD pin connected to...

Finally, do you have a schematic?

Here is my schematic at the moment (courtesy: docircuits.com), it counts down from 9 to 0

 

Hi

Here is a connect diagram for connecting a 74192 with a 7447.
The AM1 thru AM7 are measurement points for the sim. There will
really just be straight wires between the resistor pack and 7447.

 

Hi

Here is a connect diagram for connecting a 74192 with a 7447.
The AM1 thru AM7 are measurement points for the sim. There will
really just be straight wires between the resistor pack and 7447.

ahhh foolish me only thing i did wrong(?) is not connecting pin 4 of the 7447 to the supply because as much as possible, unused pins (dont care) should be connected to logic HI state according to my professor

 

ahhh foolish me only thing i did wrong(?) is not connecting pin 4 of the 7447 to the supply because as much as possible, unused pins (dont care) should be connected to logic HI state according to my professor

Hi

Well...not exactly. An unused input pin should be connected so that it's function is in its inactive logic state.
For example, on the 7447, The "LT" pin requires a low logic level to activate the Lamp Test function, so I connected to a high logic level (VDD). But the "CLR" (reset) function on the 74192 requires a high logic level to activate the CLR function, so I connected it to a low logic level(GND).

 

mhhm i got it figured after browsing on my notes thanks you all. thumbs up. +++1
I really appreciate the help.!!

 

unused pins (dont care) should be connected to logic HI state according to my professor

There are exceptions to this "rule". For example, CMOS gates dissipate very little power when not switching, so tying unused inputs HI or LO is a matter of convenience.

It would be more correct to say that unused inputs should not be allowed to float.