help about microcontroller

[-simon-]

Hi guys,
I am new in this forum. That's why i need ur help. I would like some infomation keypad using 8051 controlller. Friendly speaking, I am an engineering student. I would like to make a project on keypad development using 8051 microcontroller.

I would apprecitated it if u help me. Thanks in advance.

 

[kinjalgp]

What type of keypad are you making? Is it matrix type or do you want to interface AT keyboard to 8051?

 

[-simon-]

Thanks for the reply. The keypad i was saying is the matrix type.

 

[k7michal]

you might want to look into the 74C922 chip, it's a matrix keypad driver. It really takes all the hussle out of trying to make your own driver and it's pretty easy to interface to any uC.

Cheers.

 

[udi_hakim]

k7michal is right,

Just use the 74c922 and plain 4X4 keyboard, wire the keyboard to the X and Y inputs of the 922 , Wire the outputs of the 922 to AD0-AD3 in the 8051 , Map the 922 to an adress and then you have 2 options:
A. Using interrupt for indicating that a key is pressed (Wire DA from the 922 to the INT1 in the 8051) - it will be a very good idea

B. Use port polling (Wire DA of the 922 to any bit of P1 in the 8051) - dont forget that you will need that the proccessor will check the port constantly!

 

[kinjalgp]

Or else if you want a low cost keypad solution as 74C922 is much costlier than 8051, you can directly interface your matrix to any of the ports of 8051 and scan it at regular interval for keypress. You'll find code snippet for matrix keypad on this page
**broken link removed**

 

[-simon-]

Here is the sample.. I need guideline to create that. Anyone know any webpage or hv info in creating that, pls tell me. thks. in advance.

 

[Rizvi]

Hi All
I want need a keypad lock 4x4 using 89c51.Plus i need a program in VB which shows the status of Keypad lock i.e LOCK or UNLOCK.
Thanks

 

[srikanthsamaga]

You can check my site, I have uploaded one article on hex keypad but Used 7 segment, You can change the code according to your requirement.