4510 Cascaded Counter Preload

S

Suds

New Member

• Apr 20, 2007

• #1

Hi

I am using 2 BCD counters (4510) and 2 BCD to 7segment decoders (4511) to allow countdown from 16 to 00. I need some help finding a way to preload the BCD counters when the output of both counters are 0000 0000 to 0001 and 0110. I have tried the simulation in Multisim using an 8-input NAND and an inverter connected to the preload pin but somehow it doesn't work.

Thanks

 

ericgibbs

Well-Known Member

Most Helpful Member

• Apr 20, 2007

• #2

hi suds,
Have you set the MR pin LOW, while the PL is HIGH, when you are trying to do a parallel load?

 

S

Suds

New Member

• Apr 20, 2007

• #3

Hi ericgibbs

I will check on that shortly ... that is the least of my problems right now! The first segment doesn't operate well...all the segments stay lit up and when it counts down, the digit is seen as faintly brighter than the other segments. Don't know why this happened though.

 

S

Suds

New Member

• Apr 20, 2007

• #4

All the connections are intact so I think the breadboard is faulty...will come back with results...

Thanks

 

ericgibbs

Well-Known Member

Most Helpful Member

• Apr 20, 2007

• #5

hi suds,

A picture is worth a thousand words!.

Post a diagram so that we can help.

 

O

on1aag

New Member

• Apr 20, 2007

• #6

Suds said:

I have tried the simulation in Multisim using an 8-input NAND and an inverter connected to the preload pin but somehow it doesn't work.

Click to expand...

Hi Suds,

If you want it to reload at the maximum count you should
use a four input AND connected to QA1,QD1,QA2,QD2 and
the output goes to the preload. The counters will go to
0000 and at the next clock pulse they will reload.
I think you forgot that the 4510 is a BCD counter and it
will never reach 1111, the maximum count is 1001.

on1aag.

 

Last edited: Apr 20, 2007

S

Suds

New Member

• Apr 22, 2007

• #7

Thanks ericgibbs and on1aag...I found that the breadboard is faulty and one of the 7 segment displays LED is corrupt!

Will use the 4-input AND method...thanks for the clarification on1aag!

I really appreciate all your help.