1. Table Construction

2. Program name: Show the hexadecimal value of the R1 register on the leftmost two 7-segment displays.asm
; Title: Show the hexadecimal value of the R1 register on the leftmost two 7-segment displays
; Description: Show the value of the high nibble of R1 on the 7-segment display 3 and that of the low nibble of R1 on the 7-segment display 2.
; Note: a logic 0 lights a display segment.
start:
MOV DPH,#HIGH(table_of_number_to_7_segment_code)
MOV DPL,#LOW(table_of_number_to_7_segment_code)
repeat:
MOV A,R1
MOV B,A
; To show the low nibble
ANL A,# B
MOVC
MOV P1,# B ; to prevent trasient light
SETB P3.4 ; |
CLR P3.3 ; | enable display 1
MOV P1,A
CALL DELAY
; To show the high nibble
MOV A,B
RR A
MOV P1,# B ; to prevent trasient ligh
SETB P3.3 ; | enable display 0
CALL DELAY
JMP repeat
; a crude delay
delay:
MOV R0, #200
DJNZ R0, $
RET
table_of_number_to_7_segment_code:
db B ; 0
db B ; 1
db B ; 2
db B ; 3
db B ; 4
db B ; 5
db B ; 6
db B ; 7
db B ; 8
db B ; 9
db B ; A
db B ; B
db B ; C
db B ; D
db B ; E
db B ; F

3. 8051 Instruction: MOVC Instructions OpCode Bytes Cycles Flags
MOVC
0x93 1 2
None
MOVC
0x83
Description: MOVC moves a byte from Code Memory into the Accumulator. The Code Memory address from which the byte will be moved is calculated by summing the value of the Accumulator with either DPTR or the Program Counter (PC). In the case of the Program Counter, PC is first incremented by 1 before being summed with the Accumulator.
See Also: MOV, MOVX, Instruction Set
Operation:
MOVC
Function:
Move Code Byte to Accumulator
Syntax:
MOVC

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