LCD and KEYBOARD on PIC16F648A

[Gabi Mihai]

Hi,
I'm trying to make an home system alarm with one LCD and one KEYBOARD plus one LED and one SW but I can't use LCD and Keyboard in the same time on the same port.
Does anyone have some ideas.
Regards

[Benj]

Hello

Are you using E-Blocks or your own custom hardware?

If your using Eblocks then change the jumper setting on the LCD board from the Default setting to the Patch setting. This will enable you to rewire the LCD connections using single core wire and the turned pin sockets. The pin you need free is the LCD E pin which must be routed to pin 3 as this is not used by the keypad E-Block.

Here is a list of potential connections for the LCD.

BIT0 - 0
BIT1 - 1
BIT2 - 2
E - 3
BIT3 - 4
RS - 5

Note that you must change the LCD component connections in Flowcode to match.

Doing this should allow your LCD to work much better but maybe still result in corruption if you are doing a lot with the keypad.

[Gabi Mihai]

Hallo Benj,
I'm trying FLOWCODE (demo version) without any E-Bloks.
I've used the same port (B) for LCD and KEYBOARD and I've displayed a lot of blanks and alien figures.
I want to know if there is any way to put together this component macro or I'l change PIC to another one with more ports.
Send my a note if it is possible!
Regards

[Benj]

Hello

The simulation might have a bit of a hard time because the pins are toggling and this may be influencing the display when in real life the display would be untouched as long as the E pin was only used by the LCD.

It may be easier now for you to switch to a bigger device. The 16F877A is a good choice as it is fairly low cost but contains a lot of features such as 5 ports.