RF Module fail

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RF Module fail

Postby shahrul » Sun Jun 28, 2009 1:26 pm

I'm trying to use RF Transmitter 315MHz and RF Receiver 315MHz.
I send the UART at Transmitter and I fail to read the UART at the Receiver. Why?
If I jump the transmit and receive, the program runs succesfully.
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Re: RF Module fail

Postby ober » Mon Jun 29, 2009 10:40 am

Shahrul, what is the baud rate you use? RF module is not very good in transmitting data, you need to transmit in low speed. Around 1200 bps is good enough.
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Re: RF Module fail

Postby shahrul » Mon Jun 29, 2009 10:57 am

I'm using 9600 baud rate. So, I need to reduce my baud rate.
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Re: RF Module fail

Postby ober » Tue Jun 30, 2009 3:04 pm

Yup, change it to low baud rate. You should be able to get it at 2400 or lower. Let's us know the result. Thanks!
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Re: RF Module fail

Postby shin » Fri Dec 11, 2009 3:57 pm

ober WROTE:Yup, change it to low baud rate. You should be able to get it at 2400 or lower. Let's us know the result. Thanks!


may i know what is baud rate in RF technology...
i'm still new in RF technology..
but i need to master it to finish up my final year project..
hope u can help me to make me clear bout it

thanks
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Re: RF Module fail

Postby yonghui » Sat Dec 12, 2009 10:22 am

i think baud rate is chose depending on the capability of device or module that is being used. similar to IR data transmitting and receiving, it cannot go up to 9600bps.Maybe it's due to noises and distortion of signal at high baudrate. But, if Xbee module is used in the transmission, i am sure that the baud rate can go up to 9600bps or more.
thanks&regards,
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Re: RF Module fail

Postby joseph3600 » Mon May 07, 2012 12:12 pm

now i jz realize that the RF module jz need 1200 baud rate, but i face some problem here, i cannot compile the 1200 bps baud rate in 20MHz by using MICRO C. its said "this cannot establish this baud rate at 20MHz". So what should i do ?
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Re: RF Module fail

Postby sich » Wed May 09, 2012 2:50 am

What microcontroller are you using? Even if there's a way for you to set the baudrate to 1200bps with 20MHz crystal, there should be some great error. You may need to choose a crystal at lower frequency, like 4MHz...
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Re: RF Module fail

Postby sahniana » Tue Dec 11, 2012 7:22 pm

joseph3600 WROTE:now i jz realize that the RF module jz need 1200 baud rate, but i face some problem here, i cannot compile the 1200 bps baud rate in 20MHz by using MICRO C. its said "this cannot establish this baud rate at 20MHz". So what should i do ?


i also got a problem with 1200bps, now using 2400 bps, 4mhz crystal. seems to work.
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