VTech Alphabert s Magic Readport User Manual download pdf (Page 41)

BM Dept., Govt. Engg. College, Gandhinagar Page 41

MOV P1,#0ffh ;Make P1 output port

MOV P2,#00h ;Make P2 output port

MOV TMOD,#20h ;Timer 1, mode-2 ( auto reload mode)

MOV TH1,#0FDh ;Count value for baud rate 9600

MOV SCON,#50h ;8 bit UART mode, REN enable

MOV IE,#90h ; Enable serial interrupt and EA bit

MOV R0,#20h ;Pointer to the RAM location

SETB TR1 ;Start timer 1 to generated baud rate.

next: MOV A,@R0

MOV SBUF,A

INC R0

CJNE R0,#2Fh,next

serial: JB TI, transmit

MOV A, SBUF

MOV P0, A

CLR RI

RETI

transmit: CLR TI

RETI

END

:: WORKSHEET::

Exercise:

A. Modify program to transmit string “WELCOME TO GEC GANDHINAGAR” using

serial port. Use interrupt method and baud rate 9600.

Memory

Location

HEX

code

Label Opcode Operands Comments

1 2 ... 36 37 38 39 40 41 42 43 44 45 46 ... 79 80

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VTech Alphabert s Magic Readport User Manual Page 41