i have a joke problem,

A

alitex

New Member

• Nov 11, 2009

• #1

hi
i have a joke problem,
i use atmega16 controller in receive uart protocol from sm8223(The SM8223A is a FSK (Frequency shift keying) decoder and DTMF (Dual tone multi-frequency) receiver IC.)
when i set vcc=5V it didn't work (receive error dtmf),it really work at 5.7v only and receive correct dtmf,
any body know about this problem
thank u in advance

 

blueroomelectronics

Well-Known Member

• Nov 11, 2009

• #2

I don't get the joke?

 

K

ke5frf

New Member

• Nov 11, 2009

• #3

Might have meant, "I have a funny problem".

 

J

jimlovell777

New Member

• Nov 12, 2009

• #4

I'm guessing values you've chosen for a particular part (resistor or capacitor) is off and when you raise the voltage the frequency also shifts. It just so happens to shift where you need it at 5.7V.

 

Boncuk

New Member

• Nov 12, 2009

• #5

As far as I remember a UART is a serial device. Serial ports normally (standard) work at voltages of ±15V.

Using a MAX232 it offers an output voltage high enough using a charge pump to generate higher voltage than the usually applied VCC of 5V in logic circuits.

At 5.7V your circuit might still be critical under noisy conditions if you don't use a charge pump device. It outputs at least ±12V.

Boncuk

 

Boncuk

New Member

• Nov 12, 2009

• #6

blueroomelectronics said:

I don't get the joke?

Click to expand...

Hi Bill,

the OP is located in Syria. A joke normally means fun. All he wanted to express is a funny (strange) circuit behaviour.

Thank you for your attention.

Hans

 

H

Hamyrenz

New Member

• Dec 7, 2009

• #7

I think the atmega16 controller has requirement voltage in order to regulate. Just based on my opinion, I don't really encounter this problem. Hope you will get a solution for your problem.


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