[SOLVED] 4-bit lcd not working

[ipinimo]

hi all,

i am working on a 4-bit lcd and pic16f877a to display a message with assembly code
i discover dat if i use portD [d4:d7 or d0:d3] for the data and portA or portE for the control its works fine but with thesame code if i use any other port for control apart from portA or portE it will not work

i have cheked the code for
correct input and output pin
correct port assingment

i have cheked the code a thousand times and is correct but thesame result

can anyone tell me solution to this?

 

[millwood]

can anyone tell me solution to this?

yes - understand the code you are using.

 

[ipinimo]

thanks, i am simulating it with proteus.

if you have proteus
here is the attached project the working one and the one that is not working
i don't want to use portA or portE for the control
i really appreciate any effort or advice

 

[wp100]

Hi,

Well, without spending a good bit of time checking, not really sure why your working code is working let alone why the other one does not work.

Is it some you have written or got off the web ?

Your coding is missing important things like ADCON1 to set the Ports the Digital instead of Analogue (on Ports A an E).

You are relying on the default CONFIG settings - do you know what they are ?

Have a loook at these two LCD tutorials - they are good and do work.



PIC Tutorial* Three - LCD Modules

EPE FAQs & Resources

 

[ipinimo]

WP100 thanks
have you tested the example on the site PIC Tutorial  Three - LCD Modules ?

i tried to simulate it but not working
maybe is my software [proteus7.2]

 

[wp100]

WP100 thanks
have you tested the example on the site PIC Tutorial* Three - LCD Modules ?

i tried to simulate it but not working
maybe is my software [proteus7.2]

Not his lcd code I use some slightly different lcd code, have used some of Nigels other code ok, its all used as a reference tutorial on the Electro Tech site and his code is good.

Can you post the code asm,hex,dsn that you used -will try and run it tomorrow to see whats wrong.

 

[ipinimo]

thanks here is the simulation

 

[ipinimo]

thanks wp100

it is working now the tutorial from PIC Tutorial  Three - LCD Modules is usefull