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I not control the 2nd 8255 by 1st one.Just i connected keypad pins separately by that two 8255.
row pins connected 1st ppi.
column pins connected 1st ppi.
I check the column pins through port b of 2nd 8255.
But it does not work, its the problem..
Thanks in advance..:)
Help:embedded programming for 8051 using 8255?
I connected two 8255 ppi to 8051 to accessing keypad and lcd and other modules are connected in that.
I attached here my schematic diagram and embedded c programming for that.
while i simulating that i cant find out error.
Can anyone findout?
I connected 8255 with 8051 in address of 4000H.
also connected keypad [4*4] in port c of 8255.
We can use port c of 8255 into 2 parts using to set control word to MODE0
1) PC0 - PC3
2) PC4 - PC7
While programming(Embedded C) how can i accessing the 2 parts of Port c individually?
Thank you Bro...That link is very useful for me..:)
In 8051 while using port 0 as
1.) I/O port,it is need to use pull up resisters for port0
2.) addressdata port, No need to use pull up resisters for port0..
I will try out.If any problem I will post here..
thanks a lot again..:)
First of all I want to thank a lot to You sir..:)
We use The PPI 8255(programmable peripheral interface) for expansion of I/O ports of 8051.
So PPI interfaced with 8051 is memory mapped interfacing(i.e accessing one ppi using address at a time among many others ) in this method only we can...
I want to set portA of 8255 as O/P port in mode 0 to 8051.
So to make above one i have to put the corresponding hex code(0x83) to control register( 0x4003) of 8255 ppi ,
how can I achieve this in embedded c language(I know C only I have problem with accessing 8255 ports)?
I use keil as IDE...
xdata represents external memory. so ppi memory mapped with 8051 at 4000H (exmple).
4000H represents portA of 8255.. A0A1 are 00
4001H represents portB of 8255..A0A1 are 01
4002 represents portC of 8255.. A0A1 are 10
4003 represents control word of 8255.. A0A1 are 11
I checked that conditions and my code and circuit satisfy that.
I think you are telling problem about while simulate in proteus.
(i.e) The c program executed in keil and got hex file.
In that link where u assign the value for ControlWord of 8255 to work portA as O/P
and also control signals...
Yes jayanth sir, and I also Thanks to u a lot..:)
i read that but in that paper they dont assign value to control word of 8255 ppi.
so while simulating defaultly 8051 take as PORT A,B,C of 8255 as INPUT.
But I need 1 port as Output. So i need to assign control word..
So my question is:
I...
Hi...!
Beginner's voice: I want to set portA of 8255 is O/P in mode 0 to 8051.
So i need write hex code(0x83) to control register( 0x4003) of 8255 ppi ,
how can I achieve this in c language?
I use keil as assembler.
My error code:
xdata[0x4003]=0x83;
But keil shows the below error...
I want to set portA of 8255 is O/P in mode 0.
So i write hex (0x83) to control register( 0x4003) of 8255 ppi ,
how can achieve this?
MY CODING:
//Program to make a digital thermometer with display in centigrade scale
#include<reg51.h>
#include<absacc.h>
#define port P1
#define sec 100
char...
hi.. I am connected ppi 8255a with 8051 on address of 4000h . How can i write the control word for 8255a in c programming?
Thanks in advance.:)hi.. I am connected ppi 8255a with 8051 on address of 4000h . How can i write the control word for 8255a in c programming?
Thanks in advance.:)
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