RF Transmitter/Reciver

[Fredrick]

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]

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).

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

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

Both microcontrollers must use inverted logic.

[Fredrick]

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?

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

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]

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:

' 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] 
'

' 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]

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....... ??

[Luciano]

Hi Fredrick,

Here is how you can test the TX code and the RX with a terminal emulator.

* * *

You can test the TX code if you connect the PIC to the serial
port of your PC. The 1k resistor is mandatory.

Open your terminal emulator with these settings:

2400 baud, 8 data bits, No-parity, 1 stop bit.

'                       1k
' PIC TX pin ---------/\/\/\---------- DB9 (Pin 2) RS232 port RX data
'
'
' PIC GND -----------------------------DB9 (pin 5) RS232 port GND 
'
'
'
Counter = 65  '65 = character A
SEROUT2 TransmitterPIN,16780,["!",Counter]

If you run this code you should see in the terminal emulator: !A


* * *


You can test the RX code if you connect the PIC to the serial
port of your PC. The 22k resistor is mandatory.

Open your terminal emulator with these settings:

2400 baud, 8 data bits, No-parity, 1 stop bit.

'                       22k
' PIC RX pin ---------/\/\/\---------- DB9 (Pin 3) RS232 port TX data
'
'
' PIC GND -----------------------------DB9 (pin 5) RS232 port GND 
'
'
'
SERIN2 reciverpin, 16780, [WAIT("!"),Counter]

After you run the code you must type !A in the terminal emulator.

* * *

Note that this direct connection with series resistors works only if you
use Inverted logic for SEROUT2 and SERIN2.

Best regards,

Luciano

[Fredrick]

I give upp now..... Inverted mode does not work but True mode work just fine whit SERIN, i think it has someting to do whit noise in the air becous when i hold my hand over the antenna of the reciver it works a better but not good.

My solution will be to pull down PDN line when i don´t want to transmitt and pull it high when i want to transmitt or just drive the hole modul from an +5v high PIN on the PIC that is active when i want to transmitt and then pull it low.

Transmitter supply current is 5.2 mA so a pin from the 16F628A that have 20mA is enought.

Then i can use True mode whitout have an RF carrier when i don´t send.