HM-TR interfacing with AT89s52

HM-TR 434 is a wireless radio frequency module with default configuration(9600,8,N,1). In this post i am going to give a tutorial on interfacing HM-TR with AT89S52 microcontroller.But first you are encouraged to read this post UART in AT89s52 / Serial communication using AT89s52.The pin configuration of this module is shown below.

Figure 1:- Pin configuration of HM-TR 434

Since, the module uses TTL logic level for input and output, there is no need of line drivers while interfacing with the MCU. VCC is connected with +5 v and GND pin is connected to ground. The DRX pin and DTX pin of this module is connected with TX(P3.1) and RX(P3.0) pin of AT89s52 respectively and an Enable pin of the module is connected with P3.2(general purpose input output ) of MCU. To enter the communication mode for data transmission  CONFIG pin of the wireless module should be grounded.

After all the connection are made complete, its time to program the MCU to get the desired output. The transmitter has three switches labelled as sw1 , sw2 and sw3 and these switches are connected with first three pins of port one of MCU(transmitter). When these switches are at low logic level, wireless transmitter module transmits character A , B and C respectively. While the receiver is programmed to receive these characters and then display in 16*2 LCD. 8 bit data pins of LCD are connected with port two and rs , rw , and en pins connected with first three pins of MCU(receiver).

To download the source code, click here