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 reading Data o/p from DTMF decoder with PIC 16F84

Status
Not open for further replies.

neurostatic

Newbie level 4
Joined
Mar 9, 2004
Messages
5
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,281
Activity points
47
dtmf 16f84a

Hey people, i've connected a MITEL 8870 DTMF decoder to port b of my PIC.When i transmit a DTMF the decoder should give 5V on its data vaild
and then the same voltage on it data outputs but i'm only getting 0.75 V on these outputs of the decoder.
When i remove the pic and test the DTMF it works fine giving 5V on DV and data outputs.
Would anyone know why this voltage drop is occuring with the pic in.
The PIC pins are configured to be inputs RB0-3.
:?
 

C-Man

Advanced Member level 4
Joined
Jul 19, 2001
Messages
1,059
Helped
90
Reputation
180
Reaction score
17
Trophy points
1,318
Activity points
10,189
dtmf decoder pic

Maybe you can post your code here, might be a problem with a misconfigured I/O pin of your pic.

Also post which pin of the dtmf chip is connected to which pin of your pic.

best regards
 

pico

Full Member level 6
Joined
Sep 30, 2001
Messages
324
Helped
32
Reputation
64
Reaction score
19
Trophy points
1,298
Activity points
1,887
pic dtmf decoder

Check the resistance of the pic pin.
 

cozturk

Advanced Member level 4
Joined
Apr 2, 2002
Messages
105
Helped
3
Reputation
6
Reaction score
3
Trophy points
1,298
Activity points
906
16f84 dtmf

There was an error in the schematic of 8870 (kt3170) datasheet. I spent 1 month for this error.
 

neurostatic

Newbie level 4
Joined
Mar 9, 2004
Messages
5
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,281
Activity points
47
dtmf pic

C-Man I'll get that done as soon as i can bit busy at the mo only checking in cheers

PICO how do i check the res of an idividual pin must the pic b taken out of circuit or left in and powered up?

Cozturk What was the error u found on the datasheet it may help me.

Thanks all.
:eek:
 

cozturk

Advanced Member level 4
Joined
Apr 2, 2002
Messages
105
Helped
3
Reputation
6
Reaction score
3
Trophy points
1,298
Activity points
906
dtmf decode pic

It was about RC circuit. for output delaying. 2 sample circuit different. So you must connect RC to true pins! Look 16, 17, 18 pins
 

mbyka

Full Member level 5
Joined
May 12, 2002
Messages
297
Helped
12
Reputation
24
Reaction score
10
Trophy points
1,298
Location
from istanbul in TURKEY
Activity points
2,081

Status
Not open for further replies.

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Top