4017 Different LED count

[bigkim100]

Any way to get a 4017 (Driven by a 555) to count down rather than up. can this be switchable from counting up, to counting down LEDS?, or will I have to use something different than a 4017?
Thanks in advance for any help

 

[PETERDECO]

I believe the 4017 only counts up and returns to 0. A microcontroller, such as a PIC, can be programmed to do what you want and eliminate the need for a 555 in the process.

 

[bigkim100]

I dont know how to do programming for microcontrollers

Is there a way to do it sans Microcontroller

 

[Martaine2005]

Not sure I follow this.
You can put the LEDs in any order you like. Also diode steering for more complex control.

Martin

 

[bertus]

Hello,

Have a look at post #12 of this thread on AAC:
https://forum.allaboutcircuits.com/threads/leds-555s-flashers-and-light-chasers.19075/

Bertus

 

[AnalogKid]

Any way to get a 4017 (Driven by a 555) to count down rather than up. can this be switchable from counting up, to counting down LEDS?, or will I have to use something different than a 4017?

For non-switchable, counting down only, just connect the LEDs differently.

For switchable between up and down, you will need two chips (besides the 555). One is a 4-bit decimal or binary up/down counter. The other chip is either a 4-line to 16-line decoder, or a 3-line to 8-line decoder. Both are standard CMOS CD4000-series parts.

ak

 

[Audioguru]

Like above, a "Road Runner" circuit uses diodes to steer the outputs of a CD4017 to make a row of LEDs light back and forth.

 

[AnalogKid]

I think that is a "Knight Rider" circuit.

ak