For my clock project which I have mentioned in many other threads, I will need a 12-bit decade counter (guess why!). But the max digikey sells is 10bit. So is there a way I can take, for example, 3 4-bit counters and connect them in series so that I get a 12-bit counter?
Thanks!
baum
Should be doable. Any spec sheets we can look at?
I don't know what I should use, though. How about this one:
(74HC192E from TI)
baum
baum:
I don't know what I should use, though. How about this one:
Electronic Components and Parts Search | DigiKey Electronics
(74HC192E from TI)baum
"Cascading is effected by connecting the carry and
borrow outputs of a less significant counter to the Clock-Up
and Clock-Down inputs, respectively, of the next most
significant counter."
You're good to go.
I suspect 193, instead of 193 is binary counter, the one you want, 0-15.
Thanks. But do the decade counters auto-reset (i.e. after they have reached their MSB, do they reset on the next clock cycle)?
But I do want the 192.
I suspect 193, instead of 193 is binary counter, the one you want, 0-15.
Since I am making a clock, I want each of the 12 pins to go high in succesion for the hours.
baum:
Thanks. But do the decade counters auto-reset (i.e. after they have reached their MSB, do they reset on the next clock cycle)?
Not sure if I understand this. Do you want to know if the number goes from 9 to 0 after increment? I think so.
On my circuit simulator, the numbers go 0-1-2-3-4-5-6-7-8-9-0-1-2, etc. So do real decade counters stop at output 9 or do they "auto-reset" back to 0?
They go back to 0 per Fig 1 of the datasheet if counting up.
A decade counter counts from 0-9 and then resets to zero. It has ten states, hence "decade". Decade counters need four bits, but no more, so there is not such a thing as a decade counter with a higher number of bits. But we may have invented another snipe hunt to go along with "gofer a metric crescent wrench"; we now have "gofer a 12-bit decade counter". I like it! Sorry, all in good fun 
Decade counters, like most other sorts, can be cascaded to achieve higher divisors. And, like most others, can be rigged to reset early. So one implementation of digital clock, using BCD encoding and 7-segment displays for each digit, can be a string of 7490s fed with 1Hz and configured to ÷10, then ÷6, ÷10, ÷6, etc.
Now I'm not sure this is what you want, as you say you want 12 pins where one goes high for each hour. Certainly that is doable, but I wouldn't use a decade counter. So what sort of display are you envisioning, and what about minutes and seconds, how will those be displayed?
The thread started out talking about a clock, so I imagine once the 1Hz source is sorted out, he can have a string of counters:
0:1, 0:9, 0:5, 0:9, 0:5, 0:9 for HH MM SS
A different thread is discussing this part CD4026
Decade counter with display decode built in, so don't need another chip like 7447 on the output of the 74192.
Has the "c" bit brought out seperately, I suppose to be used to help in counting up to 5 only.
Sorry if I wasn't clear with my terminology... 
My display is going to be 12 LEDs (very simple) so I want to get an IC with an operation similar to that of a decade counter, but with 12 bits instead of 10.
i.e. decade counter counts: 0,1,2,3,4,5,6,7,8,9,0,1,2,3,4, etc.
I want one that counts: 0,1,2,3,4,5,6,7,8,9,10,11,0,1,2,3,4,5,6,7,8, etc.
and is preferably through hole.
So what I was asking is if I can use 3 4-bit "decade counters" and cascade them in some way to get 12 bits.
Thanks!
baum
So this clock displays hours only?
No!
I was planing on having the output of my minutes decade counter(s) feed to the clock input on hours: every 59 minutes, one clock cycle. I got that park working, but I just need help with the 12-hour part.
OK. How are the minutes displayed? Just curious.
So the requirement here is to take a 1 pulse/hour input and drive 12 LEDs, one for each hour, correct?
1Hz clock pulse feeds into 1s place second decade counter. When 1s place second decade counter overflows, advances 10s place second counter. When this counter hits 6 (or 60) it resets, seconds start again, but feeds clock pulse into 1s place minute decade counter, etc, etc. fast forward a bit to when minute counters combined are at "59," next clock pulse, feeds clock pulse into hour decade counter, of which I need 12 bits.
Here's a picture. The outputs of the decade counters would be connected to LEDs.
In the picture, the time shown is 06 minutes and 10 seconds. I pointed at where the hours decade would be.
I'd try a 7492 Divide-by-Twelve Counter hooked to a 74154 4-Line to 16-Line Decoder.
Okay! thanks for all the help!
baum
We will expect progress reports and pictures!
That may not be for a while... I have another clock I'm working on now....
But thanks for the help anyway!
I think this should do it, at least for demonstration purposes.
