89c51 with keypad displaying on 4 seven segment

Status
Not open for further replies.
B

Bilal Sadiq

Newbie level 5
Joined
Oct 28, 2010
Messages
10
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,281
Location
Islamabad
Activity points
1,361
hello everyone
i want some help hope anyone can help me...
i want to interface 4x4 keypad with 89c51 and want to display on 4 seven segment
suppose on first attempt i pressed 7 xxx7
on second attempt if i pressed 4 xx74
on third attempt if i pressed 1 x741
and on fourth attemp i pressed 3 7413
problem is how to display (multiplexed) using HARDWARE as well as SOFTWARE view......................
 


you must save last display value in the RAM. It will need 5 RAM address. in example, 70h, 71h 72h, 73h, 74h.
when you press a key, store the key value to 74h and then shift value of 4 RAM locations.
70h <-- 71h
71h <-- 72h
72h <-- 73h
73h <-- 74h
so, every time you must refresh your display by value of RAM address 70h - 73h.

Is it what you need?
 

First of all thank u so much (for ur reply)
i have a question that in c language for 89c51 keil how can i save the number in RAM location
please jst give me an example showing what u said to do ..
hope u will do ..
thanks once again
regards
Bilal
 

in embedded C you dont need to save it in some address specifically

unsigned char x;
x=keypad_entry;
your value will get stored in 'x' which itself is a memory location in the RAM by the name x.
now you can use x to display it on LCD
 

    V

    Points: 2
    Helpful Answer Positive Rating
Status
Not open for further replies.

Similar threads

Menu
Log in
Register
Cookies are required to use this site. You must accept them to continue using the site. Learn more…