# Creating MOD-12 Asynchronous Down Counter from MOD-16 Asynchronous Down Counter

#### Kweonamy

Joined Nov 24, 2019
5
Hello, I'm trying to create a mod-12 asynchronous down counter by modifying the mod-16 down counter. Is it possible to use the regular design of mod 16 down counter using D-type flip flop and modify the starting sequence(using set/reset) to be 1100 to create a mod-12 down counter?

#### djsfantasi

Joined Apr 11, 2010
7,752
So what’s the mod-16 down counter? What chip is used? Or if it’s constructed of discrete components you need to provide a detailed schematic. You’re looking for a chip/schematic with a preset feature!

#### dl324

Joined Mar 30, 2015
12,917
Welcome to AAC!
I'm trying to create a mod-12 asynchronous down counter by modifying the mod-16 down counter. Is it possible to use the regular design of mod 16 down counter using D-type flip flop and modify the starting sequence(using set/reset) to be 1100 to create a mod-12 down counter?
You're overthinking the problem.

Is this homework?

#### Kweonamy

Joined Nov 24, 2019
5
So what’s the mod-16 down counter? What chip is used? Or if it’s constructed of discrete components you need to provide a detailed schematic. You’re looking for a chip/schematic with a preset feature!

I'm using 4013 chip, and this is the part of the schematics that I'm using

#### Kweonamy

Joined Nov 24, 2019
5
So what’s the mod-16 down counter? What chip is used? Or if it’s constructed of discrete components you need to provide a detailed schematic. You’re looking for a chip/schematic with a preset feature!

I'm using 4013 chip, and this is the part of the schematics that I'm using

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#### Kweonamy

Joined Nov 24, 2019
5
Welcome to AAC!

You're overthinking the problem.

Is this homework?
It's a project. I have to build this as a component of my circuit, but I have to minimize the number of chips

#### dl324

Joined Mar 30, 2015
12,917
It's a project. I have to build this as a component of my circuit, but I have to minimize the number of chips
Is it a school project?

#### Kweonamy

Joined Nov 24, 2019
5

#### dl324

Joined Mar 30, 2015
12,917
For school work, we can only provide guidance.

Post the entire text of the problem and your best attempt at a solution.

#### ci139

Joined Jul 11, 2016
1,696
Is it possible to use the regular design of mod 16 down counter using D-type flip flop and modify the starting sequence(using set/reset) to be 1100 to create a mod-12 down counter?
1. It is possible to achieve this on some MOD16 counters more neatly than with some others
2. ? set/reset (you need to choose one) to be 1011 possibly -- that unless you're told to create 12 down to 1 counter which could complicate things . . . as the range you can use is either 0 to 11 (with up counter) --or-- 15 down to 4 or 0 down to 5 (with down counter) ← a one of these to decode it to 12 down to 1
about decoder chip https://www.ti.com/lit/ds/symlink/sn54f283.pdf -- e.g. to make/map a range shift (5 to 0) to (1 to 12) the 4 must be added to the 1-st

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#### ci139

Joined Jul 11, 2016
1,696
the example shows a part of how to make down counter from up counter
( if you clear the input carry and map Q0 to Q3 instead of their inversions then you can shift the count . . . up...
...but the SUM has MOD 16 without and MOD 32 with the carry applied to it )

the fast compiled Adder model :
Code:
* the listing of AdderS3.cir

* 1V to GND - Only !!!
* 2-Bit Adder with Carry I/O
* Port Map : Bit1 Bit2 Cin Cout Sum
.SUBCKT AdderS3 1 2 3 4 5
B1 7 0 V=u(V(1)*2-1)
B2 8 0 V=u(V(2)*2-1)
B3 9 0 V=u(V(3)*2-1)
R1 7 6 R=Rsum
R2 8 6 R=Rsum
R3 9 6 R=Rsum
B4 4 0 V=u(V(6)*2-1)
B5 5 0 V=u((V(6)*3-V(4)*2)*2-1)
.param Rsum=1k
.ENDS

* 9-Bit Adder with Carry I/O
* Port Map : NibbleA NibbleB Cin Cout SumNibble
.SUBCKT AdderS9 1 2 3 4 5 6 7 8 9 10 11 12 13 14 PARAMS: Vhigh=1 Vlow=0 Td=2n Vt=.5 Vh=0
B0 20 0 V=pVT
B1 21 0 V=u(V(1,20))
B2 22 0 V=u(V(2,20))
B3 23 0 V=u(V(3,20))
B4 24 0 V=u(V(4,20))
B5 25 0 V=u(V(5,20))
B6 26 0 V=u(V(6,20))
B7 27 0 V=u(V(7,20))
B8 28 0 V=u(V(8,20))
B9 29 0 V=u(V(9,20))
X1 21 25 29 30 33 AdderS3
X2 22 26 30 31 34 AdderS3
X3 23 27 31 32 35 AdderS3
X4 24 28 32 37 36 AdderS3
B11 39 0 V=uStd(V(33))
B12 40 0 V=uStd(V(34))
B13 41 0 V=uStd(V(35))
B14 42 0 V=uStd(V(36))
B10 38 0 V=uStd(V(37))
A1 38 0 0 0 0 0 10 0 SCHMITT Vhigh=pVP Vlow=pVM Td=pTT Vt=pVT Vh=pVH
A2 39 0 0 0 0 0 11 0 SCHMITT Vhigh=pVP Vlow=pVM Td=pTT Vt=pVT Vh=pVH
A3 40 0 0 0 0 0 12 0 SCHMITT Vhigh=pVP Vlow=pVM Td=pTT Vt=pVT Vh=pVH
A4 41 0 0 0 0 0 13 0 SCHMITT Vhigh=pVP Vlow=pVM Td=pTT Vt=pVT Vh=pVH
A5 42 0 0 0 0 0 14 0 SCHMITT Vhigh=pVP Vlow=pVM Td=pTT Vt=pVT Vh=pVH
.param pVP = {Vhigh}
.param pVM = {Vlow}
.param pVT = {Vt}
.param pVH = {Vh}
.param pTT = {Td}
.param pVpp = {pVP-pVM}
.func uStd(vi){pVM+u(vi*2-1)*pVpp}
.ENDS