89v51 kit: the addresses of 8255 ports and value of pins

[gemini_v440]

layout of 89v51 kit

hi ,
i m using a 89v51 kit for a uc/os-ii project. i am attaching a layout diagram of the kit.what will be the addresses of the 8255 ports????
also specify what values should the dont care pins should assume and why??

 

[IanP]

Re: layout of 89v51 kit

Each of the three 82C55s has four registers:
A ==> Port A
B ==> Port B
C ==> PortC
Control ==> Control Word

You will be using DPTR and MOVX instructions to address these registers ..
Here are valid addresses:

U14 - load DPTR with:
A ==> DPTR=0000h
B ==> DPTR=0001h
C ==> DPTR=0002h
Control==> DPTR=0003h

U15 - load DPTR with:
A ==> DPTR=0100h
B ==> DPTR=0101h
C ==> DPTR=0102h
Control==> DPTR=0103h

U16 - load DPTR with:
A ==> DPTR=0200h
B ==> DPTR=0201h
C ==> DPTR=0202h
Control==> DPTR=0203h

Which pins do you call: don't care?

Regards,
IanP

 

[gemini_v440]

Re: layout of 89v51 kit

hi ,
thanks a lot for the port addresses. i would also like to know how to send data from the 89v51 kit to the computer screen in a way to make it more interactive??

 

[IanP]

Re: layout of 89v51 kit

To make data exchange more interactive you may need to write an application similar to this one:

Regards,
IanP