Spency's digital-diy 16F PIC micro Tutorial

16F RF Module Example

RF modules make communicating with projects in isolated areas/long distances much easier, and its so simple to do. There are many different RF modules to choose from, most important of the features is the baud rate. Frequency is important aswell, however, in your program, when you use a RSOUT or RSIN command, you must specify a baud rate in the settings (declarations). If the RF module cant handle the desired baud, then the data will become scrambled and undecipherable.

I used the TLP434A and RLP434A modules, they are by no means the best, I just chose them as they were the cheapest. They can handle up to 3K baud efficiently, and in my serial programming, I always use computer equivalent bauds such as 2400/4800/9600.

Datasheets

Wiring Diagram for the receiver (PSU/Osc not shown):

Note the PIC's power supply/oscillator are not shown

Wiring Diagram for the transmitter (PSU/Osc not shown):

Note the PIC's power supply/oscillator are not shown

Now for the easy part, programming them. Just a quick 101 on serial transfer, the header "Z" is sent before the value as a marker. This is so that the receiver knows that the data its receiving is legit, well as good as it can be. The post marker "A" allows the RSIN command to recognized that the whole number has been sent. It must be an alphabetical value, and if there was no post marker, it wouldn't know if the last number it received is actually the last number, and will wait until it times out for the next value.

An example of a transmitter program;

Device 16F876A

XTAL = 4

Dim Number As Word

DECLARE RSOUT_PIN PORTA.0
DECLARE RSOUT_MODE INVERTED
DECLARE RSOUT_PACE 5
DECLARE SERIAL_BAUD 2400

ALL_DIGITAL = True

Low PORTA.0

Main:

Inc Number     ' Increment the variable

RSOUT "Z", DEC Number, "A", 13
        ' Send the value 34761 via the serial o/p
        '   with the header Z, and the footer "A"

Goto Main   ' Loop for ever

Receiver Example:

Device 16F876A

XTAL = 4

Dim Number As Word

DECLARE RSIN_PIN PORTA.0
DECLARE RSIN_MODE INVERTED
DECLARE SERIAL_BAUD 2400
DECLARE RSIN_TIMEOUT 1000

ALL_DIGITAL = True

INPUT PORTA.0

Main:

RSIN {Time_Out}, WAIT("Z"), DEC Number
        ' Wait for the value "Z" to be received and
        '  When it has, retrieve the number.
        '  Should the RSIN function not receive anything in 1000ms, it will
        '   jump to Time_Out, but if it does receive a number, then you could
        '   print it to an LCD/do what ever you wanted with it


Print At 1,1, DEC5 Number    ' Display the number on an LCD

Time_Out:
        ' This is where to go if nothing is received
        '   in 1000ms

Goto Main        ' Loop For ever

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