devices password programming

[Mel_noypi]

hi
do any one know how to program a pic to store password and also capable for the user to edit the password.i am planing to apply it to my project a security devices which requires a user password before he can enter the system.
i am using BASIC language to programm a PIC16f877.

-tnx n advnc

 

[Nigel Goodwin]

hi
do any one know how to program a pic to store password and also capable for the user to edit the password.i am planing to apply it to my project a security devices which requires a user password before he can enter the system.
i am using BASIC language to programm a PIC16f877.

-tnx n advnc

If the user needs to be able to edit the password, then you need to store the password in the data EEPROM.

 

[Mel_noypi]

do i need a external device to store it or does my pic already have it?? by the way what are the difference between an EEPROM and a flash memmory? If i only need something to store some few numbers as password only by using pic16f877 what you suggest?

:?:

 

[Nigel Goodwin]

do i need a external device to store it or does my pic already have it?? by the way what are the difference between an EEPROM and a flash memmory? If i only need something to store some few numbers as password only by using pic16f877 what you suggest?

:?:

Many PIC's have a seperate data eeprom area, the 16F877 is one that does! - the datasheet explains how to write to it and read from it. There's also an example in one of my tutorials, the last IR remote one - it's used to store the current setting for when it powers back up.

 

[sologuy7]

Yet another project..

Hi all, I'm new to this forum.. Would like to continue this topic:

From what I've learnt, the PIC 16FXXX series has only a total of 13 I/O pins. In that case, if I'm using a 4x4 keypad + transmitting modules (switchable IR/RF) that means I've already used up 8 of the 13 I/O pins.

Thus, how am i able to create password entry/editing for the microcontroller with juz 5 pins left? That's assuming i will require an LCD screen for display purposes (and mabbe add on to user-friendliness?)

Thanks for your time!

 

[akg]

Re: Yet another project..

Thus, how am i able to create password entry/editing for the microcontroller with juz 5 pins left? That's assuming i will require an LCD screen for display purposes (and mabbe add on to user-friendliness?)
Thanks for your time!

if u intend to use an LCD also, u need a micro with more ports.

 

[eblc1388]

Re: Yet another project..

Thus, how am i able to create password entry/editing for the microcontroller with juz 5 pins left? That's assuming i will require an LCD screen for display purposes (and mabbe add on to user-friendliness?)

Not enough pins? Why not try the 2-pin or 3-pin LCD interface. Or if you have lot of cash, buy a serial interface LCD.

2 Wire LCD Interface

3-wire serial LCD interface

 

[Pommie]

You can easily interface a 4x4 keypad and an LCD to a 18 pin pic.

You need
4 data lines to LCD and (via diodes) to column of keypad.
3 control lines for LCD (E, RW & RS)
4 row lines from keypad.

The diodes are needed to prevent garbled data to the LCD when lots of keys are pressed.

Thats only eleven pins. As a 16f628 can have 16 I/O pins, you can add RS232 and some blinking LEDs as well.

As for a password, will it not be entered using the keypad?

Mike.