joebloggs Posted November 17, 2006 Report Share Posted November 17, 2006 How can i create a counter that will count up to 59 but which also has the capabilities of counting down from 59 should a switch be pressed. Quote Link to comment Share on other sites More sharing options...
joebloggs Posted November 17, 2006 Author Report Share Posted November 17, 2006 also would a 74193 ic be of any use? Quote Link to comment Share on other sites More sharing options...
Ashtead Posted November 18, 2006 Report Share Posted November 18, 2006 The 74193 is a 4-bit counter so it can only count to 15. But you can cascade two of these by feeding the CARRY and BORROW outputs from the first unit into the COUNT UP and COUNT DOWN inputs of the second unit., and then make some kind of circuit that feeds clock-pulses to the first (least significant) unit's COUNT UP or COUNT DOWN inputs, depending on the position of your switch. The 74193 counts on L-H transitions on one of these inputs, while the other input should be at H.Then what is to happen when it has reached 59? Two 74193s will go on until 255 (all outputs H) and then continue from 0 again, unless some logic looks at the output lines and stop the count-up signal when it is at 59. (Obviously, it should still be able to count down from 59). Similarly, the count-down may have be blocked when the counter is at 0 (all outputs L). This all depends on what exactly the circuit is supposed to do besides counting up and down. Ashtead Quote Link to comment Share on other sites More sharing options...
joebloggs Posted November 18, 2006 Author Report Share Posted November 18, 2006 im trying to design a circuit that will act as a stopwatch so i want it to be able to count up to 59 or down from 59 and also want it to be able to be paused and reset but ive no idea how to design the circuit. Quote Link to comment Share on other sites More sharing options...
MP Posted November 18, 2006 Report Share Posted November 18, 2006 Joe,Here is a circuit for a 0 to 60 second stop watch. This should work for your purpose. It has "hold" and "reset".MP Quote Link to comment Share on other sites More sharing options...
joebloggs Posted November 18, 2006 Author Report Share Posted November 18, 2006 i have seen that there but im trying to design it in a program called quartus and i cant get all the chips. is there any substitutes available? Quote Link to comment Share on other sites More sharing options...
MP Posted November 18, 2006 Report Share Posted November 18, 2006 I am not familiar with your program, but you should look for 4511, 4518 and 4060 chips. Forget the MC1. You won't see that in your list. Does that help?MP Quote Link to comment Share on other sites More sharing options...
joebloggs Posted November 18, 2006 Author Report Share Posted November 18, 2006 none of them are available. im using an flex10k20 development board if that helps. Quote Link to comment Share on other sites More sharing options...
MP Posted November 19, 2006 Report Share Posted November 19, 2006 You might have to look at the data sheets for the parts and simulate what is actually in the individual chip packages for FPGA programming in this development package. I am not familiar with it. Perhaps another member of the forum also uses this package. You might also try a post in the programming forum.MP Quote Link to comment Share on other sites More sharing options...
mvs sarma Posted November 24, 2006 Report Share Posted November 24, 2006 How can i create Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.