Continue to Site

Welcome to our site!

Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

  • Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

binary to decade counter

Status
Not open for further replies.

yankos243

New Member
i am currently counting heart beats with an 8 bit binary counter (74hc590) but the problem is i need a decade counter so that after nine the counter rolls over to 10. right now the counter counts to 9 then displays nothing until after the 15th clock then it rolls over to 10. so my question is how can i make my 8 bit binary counter into a decade counter.
 
Here I am, not referring to a data book, but generally, all the TTL counters that end in "90" are decade counters while the ones that end in "93" are binary counters.

(1) Assuming that this is a ripple counter with active LOW reset, you can insert a NAND gate connected to the Qd and Qb outputs so that when the counter tries to go to 1010(b), it be forced to reset.

(2) Often, the decade and binary counters of the same series are pin-for-pin compatible and you can just plug in the decade version in place of the binary version.

(3) If push comes to shove, there are binary-to-BCD TTL converter chips out there floating around somewhere. Again, the data books aren't handy right now.

Dean
 
There are several solutions.

(a) Binary to BCD conversion chip, hard to find and expensive.

(b) Replace 74HC590 with several decade counters in series, like Dean Huster explained above.

(c) use an EPROM or PROM lookup table. The PROM output is programmed with the converted value and its address lines connect to the output of the 74HC590. Displays only for value 00~99 for common 8-bit EPROM. You still need to use BCD to 7 segment decoder to display the values.

(d) use a microcontroller to replace the 74HC590 altogether and performs "counting + decoding + display" in one step. Displays 0~999 because you can count more than 8-bits now, Easiest, best and cheapest but requires a bit of programming.

(e) use a CPLD in between 74HC590 and display, cost $2 US dollar, displays 000~255 or 0~255 with zero blanking. High speed. Requires programming too.
See here:

Binary to 7-segment chip

Take your pick.

Edited: add more options.
 
Last edited:
Status
Not open for further replies.

Latest threads

New Articles From Microcontroller Tips

Back
Top