SN74LV161A: Counting and RCO

Prasoon Joshi

Prodigy 30 points

Part Number: SN74LV161A

Tool/software:

Hi,

I want to make sure that I understand the data sheet correctly for this 4 bit counter.

The counter can be programmed to start up-counting from any value from the list (decimal): 0,1,2,3,4,5,6,7,8,9,15?

The RCO is asserted once the count word [Qd,Qc,Qb,Qa] = 0d9 or 0d15?

If I set the start value [D,C,B,A] = 0d0, and ENT and ENP both high (load is toggled to get the start value loaded and clock is continuously toggling), the counter will keep incrementing until it reaches 0d15? In the process it will issue 2 RCO pulses at count 0d9 and 0d15? After reaching 0d15 it will overflow and transition to 0d0?

Can someone please confirm if my understanding is correct?

Thanks.

Prasoon

17 days ago

0 Ian Graham 16 days ago

TI__Expert 5061 points

Hi Prasoon,

For this device, the count value is only 15. Any 4 digit binary values are eligible for preset (0-15 decimal) and the RCO is asserted once the count reaches 0d15. Once it reaches 0d15, counting again will cause it to overflow and return to 0d0. This can be seen in the behavioral chart shown below.

Best,

Ian

0 Prasoon Joshi 16 days ago in reply to Ian Graham

Prodigy 30 points

Hi Ian,

Thanks for the clarification. Yes, I did see this diagram. However, what threw me off was this:

Thanks.

Logic

Logic forum

SN74LV161A: Counting and RCO