Continue to Site

Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

problem with MT8870DE DTMF Decoder.

Status
Not open for further replies.

jepoy12

Junior Member level 3
Joined
Aug 19, 2011
Messages
26
Helped
1
Reputation
2
Reaction score
1
Trophy points
1,283
Activity points
1,463
Im trying to make this circuit then use a N1208 nokia Cellphone as the tone source. I putted a LED to each output to see whats going. It worked at first but without D1 ouput going high. I dont know why its not working, I checked it with the Volt Meter and it gives me .5V reading. Other outputs work properly only the D1 is not. When I rechecked I found out that I mistakenly connect the .1uF at pin 17 to the ground instead of connecting it to the voltage source.

I then fixed the wrong connection and try to rerun it again. Here comes another new problem the whole thing is not working. All the output doesnt change state when numbers are pressed and the D1 pin still on low.

Oh *** did I just wasted my 10$ for this decoder? can this problem still be fixed?
Help me please. I ordered this chip from other country and waited 5 days just to destroy it. :(

ht9170.jpg
 
Last edited:

Status
Not open for further replies.

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top