I am using AT89C2051 in my clock project and the process of scaning of segments is being carried out by using timer1 interrupt and initial time start from 12:00 when power up circuit but after 8:10 all the segments goes off even the power is on i think the microcontroller goes off. what's the solution anyone help me?
are you use float integer vareables? i think you are overloding the library!
What on earth do you mean by that?!
How can you "overload" a library?!
http://www.keil.com/forum/docs/thread11592.asp
Are you really doing this project without a debugger or without possibility of emitting trace messages on a serial port?
What have you done to try to figure out this problem?
You think the processor turns off. Shouldn't it be quite easy to verify this?
I assume that you are using a timer to step the time. Does the timer continue to run? Easy to check - let the main program busy-loop and count # of loops between ticks. If no interrupt occurs within a reasonable number of loop turns, the ISR has died.
Have you looked at numeric overflow in your variables?
Are you counting your time BCD-style or performing division/modulo on a counter?
Don't you have any spare processor pin that you can toggle in your main loop, to allow you to see what the processor does?
What happens if you configure the timer to run at a much higher frequenc - for example 60x real-time, ticking one minute every second?
Like Sherlock Holmes, you need to examine the evidence, and try to think how to explain what you see.
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Blink the Colon or decimal point 1 per second.