help me T_T about 24secs shot clock

[inhineer]

who can help me how to build a 24secs shot clock by the use of 74LS190 IC,,pls help me T_T

P.S. it should be pause and continue

 

[blueroomelectronics]

Attach your schematic. What are you using as a clock source?

 

[colin55]

Here it is put into a circuit:
**broken link removed**

From this circuit you can see how to connect a 555 to it. This will "clock" the chip.

Now get the pin out of the chip:

**broken link removed**

Now get the function(s) of the chip:

74LS190 PRESETTABLE BCD/DECADE UP/DOWN COUNTERS PRESETTABLE 4-BIT BINARY UP/DOWN COUNTERS

Now get the data sheet:
**broken link removed**
and look at the block diagram to see how the chip works.

You can see the outputs are Q0, Q1, etc.
These are outputs of a flip flop and they divide the incoming frequency by 2, so that if you have a clock from the 555 that takes 12 seconds for a HIGH and 12 seconds for a LOW, the first output Q0 will send out a HIGH for 24 seconds and a LOW for 24 seconds.
Increase the clock frequency and you can output from Q4.