AT89C51 with LCD n Keypad-help

[Shivani Joshi]

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..

thanking u all..

 

[ikalogic]

smells like a homework!

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? )

...

 

[gramo]

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..

Have you ever programmed a micro controller before? What compiler/language is your program?

 

[Shivani Joshi]

To d replies..

thanks 4 replying..
yes, it is sort of a homework..it's part of a project i'v gotta make..

i'm gonna use ASM as prgramming language
i'll use a 1X16 LCD display.. dont hav d datasheet or d component yet..i'll get it within a day..

i saw a ckt of 4X4 keypad intrfaced with d use of connectors n 4 resistors.. 'll try it out.. or if u hav betr suggestions, they r most welcome..

again, thanks 4 d reply!!

 

[ikalogic]

thanks 4 replying..
yes, it is sort of a homework..it's part of a project i'v gotta make..

i'm gonna use ASM as prgramming language
i'll use a 1X16 LCD display.. dont hav d datasheet or d component yet..i'll get it within a day..

i saw a ckt of 4X4 keypad intrfaced with d use of connectors n 4 resistors.. 'll try it out.. or if u hav betr suggestions, they r most welcome..

again, thanks 4 d reply!!

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..)

good luck

 

[Shivani Joshi]

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..)

good luck

I got it.. the 2nd one seems more suitable..
thanks a lot 4 d idea..

this site's really helpfull..
BBI..
Take Care

 

[ikalogic]

I got it.. the 2nd one seems more suitable..
thanks a lot 4 d idea..

this site's really helpfull..
BBI..
Take Care

i made this encoder circuit a couple years a go when i was building a calculator using a 8051 uC, using ASM. may you need anything, just tell me

welcome to the forum.

 

[mcs51mc]

I got it.. the 2nd one seems more suitable..
thanks a lot 4 d idea..

this site's really helpfull..
BBI..
Take Care

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)

You can, already start with the datasheet...