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Wireless Serial Communication RF Modem, 2.4 GHz, 30 meter range

Overview

CC2500 RF Module is a Transreceiver module which provides easy to use RF

communication at 2.4 GHz. It can be used to transmit and receive data

at multiple baud rates from any standard CMOS/TTL source. It works

in Half Duplex mode i.e. it provides communication in both directions, but only

one direction at same time (not simultaneously). This switching from receiver to

transmitter mode is done automatically.

RF Module can be used for applications that need two way wireless data

transmission. It features high data rate and longer transmission distance. The

communication protocol is self controlled and completely transparent to user

interface. The module can be embedded to your current design so that wireless

communication can be set up easily.

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Features

Supports Multiple Baud rates (4800/9600/19200/38400).

Supports Multiple Channel Selection (CH0/CH1/CH2/CH3).

Works on ISM band (2.4 GHz) which is reserved internationally so

no need to apply for license.

No complex wireless connection software or intimate knowledge

of RF is required to connect your serial devices.

Designed to be as easy to use as cables.

No external Antenna required.

Plug and play device.

Works on 5-9v DC supply.

Standard UART Interface.

Applications

Consumer electronics.

Wireless game controllers.

Wireless keyboard and mouse.

Weather stations.

Sensor Networks / Data collection.

Wireless metering.

RF enabled remote controls.

Access control / Identity discrimination.

Wireless data link (communication).

Wireless audio.

IT home appliance.

Smart house products / Security Systems.

Remote control / Remote measurement system.

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Specifications

Parameter Min Typ Max Units

Working Voltage 4.5 5 9 Volts

Frequency 2.4 GHz

Range 30 Meters

UART baud rate (8 bit data, no parity, 1 stop bit)

(1) 4800/9600/19200/38400 bps

Frequency channel (1)

CH0/CH1/CH2/CH3 -

Maximum Data Transmission (2) 32 Characters

Note:

1. Baud Rate & Frequency Channel Settings depends on DIP Switch

Position. (Refer Page No. 5 &6)

2. Carriage Return (CR) is required at the end of string for successful data

transmission.

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Pin Diagram

Pin Pin Name

Pin Name

RX Receive Input Input serial data of 3 to 5V logic level

TX Transmit Output Output serial data of 3V logic level

+5V Power Supply Regulated 5V supply input

Gnd Ground Ground level of power supply

Operation

This module works in half-duplex mode. Means it can either transmit or receive

but not both at same time. After each transmission, module will be switched to

receiver mode automatically. The LED for TX and RX indicates whether IC is

currently receiving or transmitting data. The data sent is checked for CRC error if

any. The RX LED is directly on TX OUT pin to indicate that actual data is

received and it is sent to output pin.

Settings

The module supports multiple baud rates and multiple frequency channels. The

settings will take place only during power on i.e. you will have to restart the

module every time you change the setting. Modifying during power up will have

no effect on operation of module.

DIP switch number 1 & 2 are used to set the baud rate whereas DIP switch

number 3 & 4 are used to select channel frequency.

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Frequency Channel Setting

Setting Frequency Channel can be used to have multiple sets operating at same

time but without Interfering with each other. The pair having same Channel

setting will be able to communicate with each other. Thus avoiding data collision

between multiple set of modules.

Frequency channel has to be set when module is OFF, as the switch positions are

read only during power up. Modifying this setting during operation will have no

effect on operation of module.

Channel settings mentioned in table given below are for Baud rate 9600 bps.

Switch Channel Setting

Channel =0

Channel =1

Channel =2

Channel =3

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Baud Rate Setting

Baud rate has to be set when module is OFF, as the switch positions are read only

during power up. Modifying this setting during operation will have no effect on

operation of module.

Baud rate settings mentioned in table given below are for Channel 0.

Switch

Baud Rate Setting

9600 bps

38400 bps

19200 bps

4800 bps

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Interfacing with 8051 Microcontroller

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Code

LCD will display data received & send string “received” as an acknowledgement.

Here baud rate setting is 9600.

#include<reg52.h>

#include <string.h>

#define cmdport P2

#define dataport P0

unsigned char ntc[32];

unsigned char current_byte = 0;

unsigned char icnt = 0;

sbit rs = cmdport^6; //register select pin

//sbit rw = cmdport^1; // read write pin

sbit e = cmdport^7; //enable pin

void ser_init(void);

void Delay250us (void);

void MsDelay (int n);

void read_ntc(void);

void lcdcmd(unsigned char item);

void lcddata(unsigned char item);

void lcdstr(unsigned char *s);

void lcdinit(void);

void Delay250us (void)

{

int j ;

for(j = 0 ; j < 100 ; j ++)

{

}

}

void MsDelay (int n)

{

int j ;

for(j = 0 ; j < n ; j ++)

{

Delay250us() ;

Delay250us() ;

Delay250us() ;

Delay250us() ;

}

}

void ser_init(void)

{

TMOD=0x20; //Timer 1 Mode 2

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TH1=-3; // Bouad Rate-9600

SCON=0x050; // 8 bit,1 stop bit

TR1=1; // start timer

ES = 1; // enable serial interrupts

}

void recieve() interrupt 4 using 1 // Function to recieve data serialy from RS232

{

if (RI)

{

ntc[ current_byte]=SBUF;

RI=0;

current_byte++;

}

}

void Ser_Write_Text(unsigned char *str)

{

unsigned char l,i;

l = strlen(str)+1; // get the length of string

for(i=1;i<l;i++)

{

SBUF=*str; // send every char one by one

while(TI==0);

TI=0;

str++;

}

}

void ser_write_no(unsigned int no)

{

SBUF=no;

while(TI==0);

TI=0;

}

void read_ntc(void) // Function to display the received string

{

unsigned char count;

lcdcmd(0x01);

MsDelay(10);

lcdcmd(0x80);

MsDelay(10);

for(count=0;count<current_byte;count++)

{

lcddata(ntc[count]);

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if (count==15)

{

lcdcmd(0xC0);

MsDelay(10);

}

}

current_byte=0;

}

//Function to send command to LCD

void lcdcmd(unsigned char item)

{

dataport = item;

rs= 0;

//rw=0;

e=1;

MsDelay(1);

e=0;

}

//Function to send data to LCD

void lcddata(unsigned char item)

{

dataport = item;

rs= 1;

//rw=0;

e=1;

MsDelay(1);

e=0;

}

//Function to display string

void lcdstr(unsigned char *s)

{

unsigned char l,i;

l = strlen(s); // get the length of string

for(i=1;i<=l;i++)

{

lcddata(*s); // write every char one by one

s++;

}

}

//Function to initialise LCD

void lcdinit(void)

{

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lcdcmd(0x38); // for using 8-bit 2 row mode of LCD

MsDelay(10);

lcdcmd(0x0E); // turn display ON for cursor blinking

MsDelay(10);

lcdcmd(0x01); //clear screen

MsDelay(10);

lcdcmd(0x06); //display ON

MsDelay(10);

}

void main()

{

EA = 1; /* enable global interrupts */

lcdinit();

MsDelay(10);

lcdcmd(0x80);

MsDelay(10);

lcdstr("CC2500");

lcdcmd(0xC0);

MsDelay(10);

lcdstr("Interface");

MsDelay(100);

ser_init();

MsDelay(50);

while(1)

{

while(current_byte==0);

read_ntc();

current_byte=0;

Ser_Write_Text("Recieved");

ser_write_no(13);

MsDelay(10);

}

}

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Interfacing with PC

Code

Code is written inVB.NET 2010 for transmitting & reception of data to & from

CC2500 module. Here baud rate setting is 9600 bps.

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Imports System

Imports System.IO.Ports

Public Class Form1

Dim WithEvents port As SerialPort = New _

System.IO.Ports.SerialPort("COM3", 9600, Parity.None, 8, StopBits.One)

Private Sub Form1_Load(ByVal sender As Object, ByVal e As _

System.EventArgs) Handles Me.Load

CheckForIllegalCrossThreadCalls = False

If port.IsOpen = False Then port.Open()

End Sub

Private Sub port_DataReceived(ByVal sender As Object, ByVal e As _

System.IO.Ports.SerialDataReceivedEventArgs) Handles port.DataReceived

Label1.Text = port.ReadExisting

End Sub

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs)

Handles Button1.Click

port.Write(TextBox1.Text & vbCr)

End Sub

Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs)

Handles Button2.Click

Application.Exit()

End Sub

End Class