1. I have project to implement timer in presentation which need to interface LCD and keypad with 16f873a. the range of time is between 5 min until 30 min..user will key in their needed time by using keypad and lcd will be more focus to display timer(stopwatch).
As far i understand is that you want to make a timer which ranges from 5-30 minutes.user will enter the required time by keypad and it will be display on lcd.
It also start the counter/timer and when ever the timer value matches with the user entered value the timer stops.Is it right?
In which phase you have a problem,interfacing keypad and lcd with microcontroller OR timer problem OR you want a complete idea.
Tq for your kindly respond...
your understanding about my program is exactly right...I need a complete idea.now for hardware part I used 16f877a..LCD data connected to Port B,Keypad connected to PortD...
the problem now i dont know how to interface this two component in the sort of programming.. and also timer
Which compiler you are using for programming.
If you are using CCS compiler then you can find lot of examples how to interface keypad and lcd with microcontroller at www.ccsinfo.com/forum .
You can use timer to generate interrupt after every 1sec, then increament your variable let say Sec,when sec will be greater than 59,then increament min and start sec from 0 again,when you reaches at the desired min's value then stop the counter/disable the timer.