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RF Module microcontroller interfacing Help

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anandpv2009

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RF Module Help

Anyone have any experience with the below shown RF module and microcontroller interfacing

**broken link removed**


The RF modules works fine with HT12E and 12D but not with MCs UART. I tried it with a baud of 300 but failed. It works fine with only baud less than 40... \


Anyone know how connect it at higher baud rate....
 

I Tried with PIC microcontrollers, and it works OK. But, you must know some tricks to do it:

- The output in the receiver is allways with so many noise, receiver pin (RXD) is continuos fliping the values, so, it "confuses" the microcontroller. But when true data is comming from the transmiter, the output is very stable.
- The TX pin in the microcontroler, is normally in the 1 state, so, it's allways transmiting.

Invert the TXD pin, so, only when the microcontroller send '0's it will turn on the transmiter
Set the speed at highter bit rate, I used 4800bps is better than lower bit rates
Send redundant data, send a easy know header in your packets that the receiver can easy sinchronice, like 0x55 or 0xAA data, when you receive it know that you can start receiving the rest of packet.

Hope that advises helps you.:D
Have a nice day
 

    anandpv2009

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I tested the above..

Your INVERTand 0x55 techniques are good.

But my modules are not responding after increasing baud....


Could you please give that piece of code in ccs...




Thanks......
 

anandpv2009,

Did you put your modules on a osciloscope. What are the signals that apears on RXD pin and TXD when you transmit a square wave? Did you see a square wave in RXD when you put a square wave in the TXD pin?
 

I don't have CRO. I am using PCI slot (computer) CRO but now it is not working....
:cry::cry:
 

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