Hello evry 1..
i need a ckt diagram 4 a project in which i'v gotta interface microcontroller AT89C51 to an LCD display (1row 16char) and a Keypad (4cros4 matrix)
..
i require a ckt with all misc components and connection..
are you going to program in C or ASM?
Do you have the LCD yet? have a datasheet?
have you thought how do you want to interface the 4X4 keypad? (scanning or encoding? )
Hello evry 1..
i need a ckt diagram 4 a project in which i'v gotta interface microcontroller AT89C51 to an LCD display (1row 16char) and a Keypad (4cros4 matrix)
..
i require a ckt with all misc components and connection..
as for the key pad.. there are 2 common ways to do it
1) the easy circuit but complicated program (specially in ASM). which is probably the one you found. and it needs the whole 8 pins of a port.
2)Another way is to 'encode' 15 keys into a 4 bit binary numbre (Nible)
this technique is much more easier in programming, but a litle more dificult in the circuit... (if you'r familiar with digial logic design, then it's a piece of cake..)
as for the key pad.. there are 2 common ways to do it
1) the easy circuit but complicated program (specially in ASM). which is probably the one you found. and it needs the whole 8 pins of a port.
2)Another way is to 'encode' 15 keys into a 4 bit binary numbre (Nible)
this technique is much more easier in programming, but a litle more dificult in the circuit... (if you'r familiar with digial logic design, then it's a piece of cake..)
2nd one can have only 15 keys, your key pad has 4*4= 16 keys.
What will you tell the user: "Don't use that key, it's a spare one."
No, go for the first option. Less hardware, more software.
The fun in µC is coding not soldering !
So use your brains, draw a schematic, make a flow chart, (use Google or others) propose something here and you can be sure help is on the way. But it has to come from you.
I have working hard- and software (ASM) for both keypad and LCD (as long it has a Hitachi HD44780 controller)