Hello all,
I am trying to connect my keypad to the matrix dot screen of the microcontroller 8051 by using the assembly language, but I dont know what it is the wrong with the code, can anyone help me with it ?? thanks
keyport equ P2 ;Keypad port connected here
col1 equ P2.0 ;Column 1
col2 equ P2.1 ;Column 2
col3 equ P2.2 ;Column 3
col4 equ P2.3 ;Column 4
ORG 0000H
LJMP MAIN
MAIN:
keyval equ 30H ;To store key number
pressed bit 0H ;Flag
key_init:
mov keyport,#0FH ;Make rows as o/p and col as i/p
ret
get_key:
mov keyval,#0 ;reset the number
mov keyport,#7FH ;make Row1 low
acall read_col ;read columns
jb pressed, done ;check if flag is set
mov keyval,#4 ;if not then read next row
mov keyport,#0BFH ;make Row2 low
acall read_col ;read columns
jb pressed, done ;check if flag is set
mov keyval,#8 ;if not then read next row
mov keyport,#0DFH ;make row3 low
acall read_col ;read columns
jb pressed, done ;check if flag is set
mov keyval,#12 ;if not read row4
mov keyport,#0EFH ;make row4 low
acall read_col ;read columns
done:
ret
read_col: ;read columns routine
clr pressed ;reset the flag
jb col1, nextcol ;check if first key is pressed
jnb col1,$ ;if yes then wait for key release
setb pressed ;set the flag
ret
nextcol: ;read col2
jb col2, nextcol1 ;check if second key is pressed
jnb col2,$ ;if yes then wait for key release
inc keyval ;its key number 2
setb pressed ;set the flag
ret
nextcol1: ;read col3
jb col3, nextcol2 ;check if third key is pressed
jnb col3,$ ;if yes then wait for key release
inc keyval ;its key 3
inc keyval
setb pressed ;set the flag
ret
nextcol2: ;read column 4
jb col4, exit ;check if fourth key pressed
jnb col4,$ ;if yes then wait for key release
inc keyval ;its key 4
inc keyval
inc keyval
setb pressed ;set the flag
ret
exit: ;if no key is pressed
clr pressed ;clr the flag
clr keyval ;reset the number
ret
LJMP MAIN
$include(t89c51cc01.inc)
end
I am trying to connect my keypad to the matrix dot screen of the microcontroller 8051 by using the assembly language, but I dont know what it is the wrong with the code, can anyone help me with it ?? thanks
keyport equ P2 ;Keypad port connected here
col1 equ P2.0 ;Column 1
col2 equ P2.1 ;Column 2
col3 equ P2.2 ;Column 3
col4 equ P2.3 ;Column 4
ORG 0000H
LJMP MAIN
MAIN:
keyval equ 30H ;To store key number
pressed bit 0H ;Flag
key_init:
mov keyport,#0FH ;Make rows as o/p and col as i/p
ret
get_key:
mov keyval,#0 ;reset the number
mov keyport,#7FH ;make Row1 low
acall read_col ;read columns
jb pressed, done ;check if flag is set
mov keyval,#4 ;if not then read next row
mov keyport,#0BFH ;make Row2 low
acall read_col ;read columns
jb pressed, done ;check if flag is set
mov keyval,#8 ;if not then read next row
mov keyport,#0DFH ;make row3 low
acall read_col ;read columns
jb pressed, done ;check if flag is set
mov keyval,#12 ;if not read row4
mov keyport,#0EFH ;make row4 low
acall read_col ;read columns
done:
ret
read_col: ;read columns routine
clr pressed ;reset the flag
jb col1, nextcol ;check if first key is pressed
jnb col1,$ ;if yes then wait for key release
setb pressed ;set the flag
ret
nextcol: ;read col2
jb col2, nextcol1 ;check if second key is pressed
jnb col2,$ ;if yes then wait for key release
inc keyval ;its key number 2
setb pressed ;set the flag
ret
nextcol1: ;read col3
jb col3, nextcol2 ;check if third key is pressed
jnb col3,$ ;if yes then wait for key release
inc keyval ;its key 3
inc keyval
setb pressed ;set the flag
ret
nextcol2: ;read column 4
jb col4, exit ;check if fourth key pressed
jnb col4,$ ;if yes then wait for key release
inc keyval ;its key 4
inc keyval
inc keyval
setb pressed ;set the flag
ret
exit: ;if no key is pressed
clr pressed ;clr the flag
clr keyval ;reset the number
ret
LJMP MAIN
$include(t89c51cc01.inc)
end
