DESIGN OF WIRELESS DATA MODEM - Computer Programming

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# DESIGN OF WIRELESS DATA MODEM

###### EXPT NO: 4

AIM:

To communicate between two microprocessors using wireless data modems.

APPARATUS REQUIRED:

1.8085 microprocessor kit - 2
2. Wireless data modem – 2

DESIGN:

Baud rate calculation:
Baud rate * Required baud rate input to 8251=  Required clock
16*300 = 4800
Therefore, Required clock input to 8251 = 4800 Hz
Count value = Clock input to 8253 / Required clock input to 8251
=1.536*10^6 / 4800
= 320 = 140 H.

### HARDWARE DESCRIPTION OF VCT-10A

#### HARDWARE DESCRIPTION OF VCT-10B

ALGORITHM FOR TRANSMITTER:

1. Initialize the serial port for data transmission.
2. Set baud rate as 300.
3. Initialize the memory pointer of the data to be transmitted.
4. Set a counter for verification of EOF.
5. Get the data from the consecutive memory locations and transmit it till EOF is reached.
6. Reset the system.

##### FLOWCHART FOR TRANSMITTER

PROGRAM FOR TRANSMITTER:

4100                  21,00,45                                    LXI             H, 4500H

4103                  3E, 36                                       MVI                        A, 36H   Set the timer

4105                   D3, 0B                                     OUT                                       0BH Channel 0 in mode 3

4107                 3E, 40                                                                             MVI            A, 40H            Set baud rate as 300

4109                    D3, 08                                     OUT             08H

410B                 3E, 01                                        MVI             A, 01H

410D                  D3, 08                                      OUT             08H

4111                   DB, 05            CHECK             IN              05H

4113                  E6, 04                                         ANI             04H                  Check transmitter empty

4115                 CA, 11, 41                                    JZ             CHECK

4118                  7E                                              MOV            A, M

4119                 D3, 04                                       OUT              04H

411B               23                                                INX               H

411C                 FE, 3F                                       CPI               3FH                    Check EOF

411E                C2, 0F, 41                                   JNZ            RELOAD

4121                 0D                                                  DCR          C

4122               C2, 11, 41                                   JNZ               CHECK

4125                     CF                                         RSTI                                            Reset

1.Initialize the serial port for data reception.
2.Set baud rate as 300.
3.Initialize the memory pointer for the data to be EOF.
4.Set a counter for verification of EOF.
5.Receive the data and store it in the consecutive memory locations till EOF is reached.
6.Reset the system.

4100                  21,00,45                                      LXI           H, 4500H

4103                  3E, 36                                         MVI           A, 36H              Set the timer

4105                   D3, 0B                                      OUT            0BH                  Channel 0 in mode 3

4107                 3E, 40                                                                               MVI  A, 40H        Set baud rate as 300

4109                  D3, 08                                         OUT           08H

410B                 3E, 01                                          MVI            A,01H

410D                  D3,08                                         OUT             08H

4113                  E6, 02                                       ANI 02

4115            CA, 11, 41                                       JZ                  CHECK

4118               DB, 04 IN                                   04H

411A                77                                                MOV           M, A

411B                  23                                              INX                        H

411C                D3, 04                                                                               CPI           3FH                 Check EOF

4121                  FE, 3F                                       DCR             C

4122                0D                                                                                       JNZ           CHECK

4125                 CF                                              RSTI                                            Reset

TABULATION:

RESULT:
Thus the communication between two microprocessors is made using wireless data modem.