RF Transmitter/Reciver

**Fredrick** · - 16th February 2008, 17:57

This codes works pretty well for upp to 50 meter if the antenna of the recviver is not moving and it uses True mode and SERIN/SEROUT and it does´t work with Inverted mode????

If i´m in the range of 30 meters it does´t miss any numbers or loos the value in the variable "Check".

Why does the the Serin2 and Serout2 thats used in the BS2 sampel for these 2 modules don´t work at all.

Are you living in a city area?

No.

If not, it is possible that there is another transmitter within 500m?

I don´t think so but you never know.

Do you have an oscilloscope?

Yes at work, but not here at home.

I´m going to test later whit a wire direkt to the PIC.

Maybe this modules does´t work better and this?

What is the diffrens for the LINX modules to be driven by Inverted mode or True mode?
inverted mode (as in the BS2 from Parallax sampel) shold be the best for these modules, or?

Code:

<html>
<head></head>
<body><!--StartFragment--><pre><code><font color="#008000"><i>'****************************************************************
'*  Name    : Transmitter.BAS                                   *
'*  Author  : Fredrick                                          *
'*  Notice  : Copyright (c) 2008                                *
'*          : All Rights Reserved                               *
'*  Date    : 2008-02-13                                        *
'*  Version : 2008-02-16                                        *
'*  Notes   : PIC16F628A @ 4MHz INTORC                          *                                   
'*          : Anv&auml;nder INTORC BIT 4 1-0 FOSC 2 - FOSC0 = 1 0 0  *
'*          : TransmitterPIN = PORTB.4                          *
'*          : LEDpin = PORTB.0                                  *
'****************************************************************
</i></font>CMCON = <font color="#808080">7 </font><font color="#008000"><i>'Alla I/O Digitala
</i></font>LEDPin <font color="#000080">VAR </font>PORTB.<font color="#808080">0
</font>TransmitterPIN <font color="#000080">VAR </font>PORTB.<font color="#808080">4
</font><font color="#000080">INCLUDE </font><font color="#FF0000">&quot;modedefs.bas&quot;
</font>Check <font color="#000080">VAR BYTE
</font>Counter <font color="#000080">VAR BYTE
CLEAR

</font>Check = <font color="#808080">254

</font>Main:
    <font color="#000080">HIGH </font>LEDPin    
    <font color="#000080">SEROUT  </font>TransmitterPIN,T2400,[<font color="#808080">$55</font>,<font color="#808080">$55</font>,<font color="#808080">$55</font>,<font color="#808080">63519</font>,Counter,Check]
    <font color="#008000"><i>'PULSOUT TransmitterPIN, 1200 
    'SEROUT2 TransmitterPIN, 16468, [&quot;!&quot;, Counter.HIGHBYTE, Counter.LOWBYTE]
    </i></font><font color="#000080">LOW </font>LEDPin
    Counter = Counter + <font color="#808080">1
    </font><font color="#000080">PAUSE </font><font color="#808080">100
</font><font color="#000080">GOTO </font>Main
<font color="#000080">END 


</font></code></pre><!--EndFragment--></body>
</html>

Code:

<html>
<head></head>
<body><!--StartFragment--><pre><code><font color="#008000"><i>'****************************************************************
'*  Name    : Reciver.BAS                                       *
'*  Author  : Fredrick                                          *
'*  Notice  : Copyright (c) 2008                                *
'*          : All Rights Reserved                               *
'*  Date    : 2008-02-13                                        *
'*  Version : 2008-02-15                                        *
'*  Notes   : PIC16F872 @ 20 MHz                                *
'*                                                              *                                                              *
'*                                                              *
'****************************************************************
</i></font>ADCON1 = <font color="#808080">7 </font><font color="#008000"><i>' Alla digitala
</i></font><font color="#000080">DEFINE </font>OSC <font color="#808080">20
</font><font color="#000080">DEFINE </font>LCD_COMMANDUS <font color="#808080">3000   </font><font color="#008000"><i>'Set command delay time in us
</i></font><font color="#000080">DEFINE </font>LCD_DATAUS <font color="#808080">200       </font><font color="#008000"><i>'Set data delay time in us
</i></font><font color="#000080">DEFINE </font>DEBUG_BAUD <font color="#808080">2400 
</font><font color="#000080">DEFINE </font>DEBUG_MODE <font color="#808080">0
</font><font color="#000080">DEFINE </font>DEBUG_REG PORTC
<font color="#000080">DEFINE </font>DEBUG_BIT <font color="#808080">7   </font><font color="#008000"><i>'PORTC.7 OLIMEX RS232Board
</i></font><font color="#000080">INCLUDE </font><font color="#FF0000">&quot;modedefs.bas&quot;
</font>ReciverPIN <font color="#000080">VAR </font>PORTC.<font color="#808080">0
</font>Check <font color="#000080">VAR BYTE
</font>Counter <font color="#000080">VAR BYTE

CLEAR
PAUSE </font><font color="#808080">500

</font>Main:
    <font color="#000080">SERIN  </font>ReciverPIN,T2400,<font color="#808080">500</font>,NoSignal,[<font color="#808080">63519</font>],Counter,Check
    <font color="#008000"><i>'SERIN2 reciverpin, 16468, [WAIT(&quot;!&quot;), Counter.HIGHBYTE, Counter.LOWBYTE]
    </i></font><font color="#000080">IF </font>Check = <font color="#808080">254 </font><font color="#000080">THEN 
        GOSUB </font>LCD
    <font color="#000080">ELSE
        GOSUB </font>NoSignal
    <font color="#000080">ENDIF    
GOTO </font>Main

LCD:
    <font color="#000080">LCDOUT </font><font color="#808080">$FE</font>,<font color="#808080">1  
    </font><font color="#000080">LCDOUT </font><font color="#808080">$FE</font>,<font color="#808080">$80</font>, #Counter
    <font color="#000080">DEBUG </font>#Counter, <font color="#808080">13</font>,<font color="#808080">10
    </font><font color="#000080">PAUSE </font><font color="#808080">50    
</font><font color="#000080">GOTO </font>Main

NoSignal:
    Check = <font color="#808080">0
    </font><font color="#000080">LCDOUT </font><font color="#808080">$FE</font>,<font color="#808080">1  
    </font><font color="#000080">LCDOUT </font><font color="#808080">$FE</font>,<font color="#808080">$80</font>, <font color="#FF0000">&quot;No signal!&quot;
    </font><font color="#000080">DEBUG </font><font color="#FF0000">&quot;No signal!&quot;</font>, <font color="#808080">13</font>,<font color="#808080">10
</font><font color="#000080">GOTO </font>Main
<font color="#000080">END 
</font></code></pre><!--EndFragment--></body>
</html>

**Luciano** · - 16th February 2008, 18:09

Originally Posted by Fredrick

What is the diffrens for the LINX modules to be driven by Inverted mode or True mode?

When Inverted logic is used there is no RF carrier while the data line is idle.
The power amplifier is activated only when a logic "1" is present on the DATA line.

This is what you have on the DATA line when you use the Inverted logic.

Best regards,

Luciano

**Fredrick** · - 16th February 2008, 18:50

Ok, and in True mode you have RF carrier when the DATA line i in idle.

But i´m still not understanding why its a problem to drive it in true mode, and in my case i have to drive it in true mode for inverted mode does´t work at all.

**Luciano** · - 16th February 2008, 18:57

Before you test with the RF modules, make sure that your system works when the
two microcontrollers are connected with a 1k ohm resistor.
Make sure that the two PIC microcontrollers share the same ground. (GND).

Code:

PIC #1                 PIC #2
             1k
TX Pin-----/\/\/\------RX pin

GND -------------------GND

Both microcontrollers must use inverted logic.

**Fredrick** · - 16th February 2008, 19:55

I have done the Test now.. and here we have the problem

It dosen´t work whit the BS2 code (SERIN2/SEROUT2) whit wires between the pic´s but the other code whit SERIN and SEROUT works fine.

What could be the problem?

Code:

SERIN2 reciverpin, 16468, [WAIT("!"),Counter]

Code:

PULSOUT TransmitterPIN, 1200 
SEROUT2 TransmitterPIN, 16468, ["!",Counter]

i´m not sure if the "16468" in the BS2 program shold be the same in a PBP program, i dont understand how to set those bits. but if there shold be "16468" then what else could be wrong?

EDIT:
Just find that 9600 baud may be unreliable with 4MHz clock, but it´s still not working when i try to lower the baud to 2400.
It´s not working in inverted mode whit both SERIN/SEROUT and SERIN2/SEROUT2

http://www.microengineeringlabs.com/.../ser2modes.htm

What are i´m doing wrong?

EDIT2:
Can it have someting to do whit that i´m using a 4MHz inernal RC on the transmitter? shold i clock it up to 20MHz whit an external crystal like the reciver?

**Luciano** · - 17th February 2008, 09:46

Hi Fredrick,

A sync pulse of 3000 µs is what is used in the BS1 example visible at page 5 of this doc:
http://www.parallax.com/Portals/0/Do...ceive-v1.0.pdf
(In the BS1 sample code the baud rate is 2400).

I am not a PicBasic Pro user or a Basic Stamp user, so what I can do is very limited
and based only on the user manuals.

Here is my version of the PBP code:

Code:

' Transmitter code 
' (Clock = 4MHz).
'
' At 4MHz, a PULSEOUT of 300 is OK. 
' 300 * 10 µs = 3000 µs 
' (See PBP Manual PULSEOUT). 
'
' BAUD MODE = 16780 (Baud rate 2400, 8-bit, no-parity, inverted, output DRIVEN).
'
'
PULSOUT TransmitterPIN, 300  ' sync pulse of 3000 µs 
SEROUT2 TransmitterPIN,16780,["!",Counter] 
'

Code:

' Receiver code 
' (Clock = From 4MHz to 20 MHz).
'
' BAUD MODE = 16780 (Baud rate 2400, 8-bit, no-parity, inverted).
'
'
SERIN2 reciverpin, 16780, [WAIT("!"),Counter]
'

Best regards,

Luciano

**Fredrick** · - 17th February 2008, 12:23

Does´t work....

The PIC (16F872) stops at
SERIN2 reciverpin, 16780, [WAIT("!"),Counter]

Is there a bug in PBP like the one whit OWOUT that make a never ending loop
I have version PBP 2.50a

http://www.picbasic.co.uk/forum/show...79&postcount=4

Note that both SERIN and SERIN2 make´s the PIC stops when i try to use them whit Inverted mode. whit SERIN and True mode it works..

UPDATE:
When i remove "PULSOUT TransmitterPIN, 300" it works....... ??

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