hey!! i am trying to decode a DTMF tone by using a decoder chip then i send it to the microcontroller at89s52 and then display the output in the lcd but when the key on the telephone set is pressed 1 only one time, the no. 1 keeps on displaying...how do i solve it?? plz help!!
The first thing you have to do is to determine what causes it!
Once you know what the causes is, the fix should follow naturally.
"the key on the telephone set is pressed 1 only one time"
Do you mean pressed and held - giving a continuous tone - or pressed and released?
Is the decoder chip behaving in accordance with its Datasheet?
thankyou andrew the keypad in the telephone is pressed only once and then released...but the lcd shows 1 repetedly!!!
The most important tool for debugging is the one between you ears - you need to think about what could possibly be causing this.
What thinking have you done?
What things do you think could possibly cause this behaviour...?
whenever the key in the telephone set is pressed and released, the four bit output get latched..i think thats the main problem.
OK - so define some test or experiment to confirm that.
www.8052.com/.../120313
Then, when you're sure what the problem is, you can start to think about how to fix it...