Bits transmission

Hello!

For a project, I need to transfer data by RF between two PICs. I need to transmit two bits every 1/50s and to decode them (juste want to compare them to a model and see if it's true or false) at the reception. Is their any way to do this without using a serial connection? I don't want the serial because I don't want to change the speed of the transmission. Thanks in advance,

JFDuval said:

Hello!

For a project, I need to transfer data by RF between two PICs. I need to transmit two bits every 1/50s and to decode them (juste want to compare them to a model and see if it's true or false) at the reception. Is their any way to do this without using a serial connection? I don't want the serial because I don't want to change the speed of the transmission. Thanks in advance,

Click to expand...

By definition, an RF connection is a serial one, I don't see what using a serial connection has to do with changing the speed of the transmission?.

Also, why not do the comparison at the transmitter end?, and simply send a signal for either true or false?.

For a reliable RF link you should use some type of coding, Manchester coding is the usual one employed.

Hello!

I'm new to uC and I was thinking that for a serial transmission you would need to send data at a precise rate. Now that you told me it's false, I'll use USART of the pic to transmit my bits. I'll not use the transmitter to check the condition for the simple reason that I'll have up to 16 different bytes to test. Also, how am I supposed to compare a byte with another? Is it simply by:

Thanks in advance,

The speed of your 2 USARTS needs to be the same if you are using asyncronous mode. Asyncrounous means that there isn't a clock to tell when the data is valid. If you use syncrounous mode the timing won't be as important because there is a clock to tell the receiver that the data is valid.

If you just want to send single bits whenever you want you can use simple handshaking. Handshaking takes 2 extra lines. The sender puts the bit on a pin and sets a "data valid" line to tell the other controller that the bit is ready to be read. The receiver then reads the bit and sets a "data received" line to tell the sender that it received the bit correctly. This setup lets you transmit at whatever speed you like because the two sides will wait for each other using the "data valid" and "data received" lines.

By definition, an RF connection is a serial one

Click to expand...

Don't like to split hairs, but have you heard of digital terestrial television? It's massively parallel!

JohnBrown said:

By definition, an RF connection is a serial one

Click to expand...

Don't like to split hairs, but have you heard of digital terestrial television? It's massively parallel!

Click to expand...

As it's not available where i work, no! :lol:

I would also disagree that it's actually a parallel transmission system, and for the context of this thread it make no difference. The modulation employed is intended to help reduce the effects of ghosting, not to provide a parallel transmission system.

Actually it's used as a parallel transmission scheme. In the UK, there are nearly 2000 carriers, each of which is amplitude and phase modulated to carry either 4 or 6 bits per "symbol". Sure, it's designed to cope with multipath reception, and other types of interference. But it's also designed as a parallel system. So is ADSL (and WiFi, I believe).
However, as you say, Nigel, it's entirely irelevant to this thread, but very interesting none the less! All that clever processing just so that we can watch trashy soaps or download porn!

Nigel Goodwin said:

For a reliable RF link you should use some type of coding, Manchester coding is the usual one employed.

Click to expand...

Can you give me some details please?

JFDuval said:

Nigel Goodwin said:

For a reliable RF link you should use some type of coding, Manchester coding is the usual one employed.

Click to expand...

Can you give me some details please?

Click to expand...

If you google for it there are many links on the net, one place you might start is .