74HC390 table of pin connections?

[Gillie]

Hello

First question here. I want to experiment with 74HC390 chip. I know the pin strappings for divide by 4 (example (14 to 2), (15 to 3), (2,4,8,12,14 to Ground), 1 in and 13 out) and divide by 100 from a Mr Carlson's Lab YouTube clip, but I would like to find the pin strappings for the other possibilities (I believe I could divide by 2,5,10,20,25,50?). Someone must have produced a table, but extensive Googling fails to find it!

 

[Audioguru]

Did you look at the datasheet of the SN74HC390? Oh, Texas Instruments say it is obsolete do not show its datasheet.

 

[Gillie]

Did you look at the datasheet of the SN74HC390? Oh, Texas Instruments say it is obsolete do not show its datasheet.

Thanks for the speedy reply! Unfortunately, I cannot glean the info I need from the datasheets.

 

[hevans1944]

Thanks for the speedy reply! Unfortunately, I cannot glean the info I need from the datasheets.

Well, actually you can if you understand how the counters work. Review this Texas Instruments datasheet for this obsolete and no longer manufactured part. Then breadboard a trial circuit using a low-speed clock, typically a de-bounced push-button switch, and a logic probe to see what is going on.

 

[Herschel Peeler]

Hello

First question here. I want to experiment with 74HC390 chip. I know the pin strappings for divide by 4 (example (14 to 2), (15 to 3), (2,4,8,12,14 to Ground), 1 in and 13 out) and divide by 100 from a Mr Carlson's Lab YouTube clip, but I would like to find the pin strappings for the other possibilities (I believe I could divide by 2,5,10,20,25,50?). Someone must have produced a table, but extensive Googling fails to find it!

See attached pdf.

 

[Herschel Peeler]

See attached pdf.

OOPs! After looking at it the Divide by 25 doesn't work. I will have to reconsider that.

 

[Herschel Peeler]

OOPs! After looking at it the Divide by 25 doesn't work. I will have to reconsider that.

Divide by 25 reconsidered.

 

[Herschel Peeler]

See attached pdf.

Even simpler. Five fives. One last time.

 

[Herschel Peeler]

Hello

First question here. I want to experiment with 74HC390 chip. I know the pin strappings for divide by 4 (example (14 to 2), (15 to 3), (2,4,8,12,14 to Ground), 1 in and 13 out) and divide by 100 from a Mr Carlson's Lab YouTube clip, but I would like to find the pin strappings for the other possibilities (I believe I could divide by 2,5,10,20,25,50?). Someone must have produced a table, but extensive Googling fails to find it!

The 74xx390 is two divide-by-ten counters. Each section has a divide-by-two and a divide-by-five part. So all you have to do is break down the count you want (in your case) into 2's, 5's, and 10's and use the sections as they are designed. Take another look at the data sheet, more closely this time.
Divide-by-two uses one divide-by-two section of one counter. Divide-by-five uses one divide-by-five section of a counter. Divide-by-ten just tie one divide-by-two to one divide-by-five and you have a divide-by-ten. It doesn't matter which you do first.. Divide-by-twenty, is a divide-by-ten and a divide-by-two. It doesn't matter which you do first. Divide-by-twenty-five is two divide-by-fives. Divide by fifty is a divide-by-five and a divide-by-ten. It doesn't matter which you do first.-
For counts other than something divisible by 2 or 5 you need to use a AND gate and take the high outputs of one of the divide-by-five sections. Straight binary stuff. (Learn binary.)