any help me! : 8051 Microcontroller Projects AVR PIC Projects Tutorials Ebooks Libraries codes

Forums

Rickey's World :: Discussion Forums :: Discuss and Learn :: 8051 Discussion Forum		<< Previous thread \| Next thread >>
any help me!


Moderators: Ajay Bhargav, Arun Kumar V, pdi33, Shailesh NAYAK, ۞ TPS ۞, shyam, sashijoseph, ExperimenterUK, DavesGarage

Author

Post

vanbayhoang

Sat Oct 31 2009, 06:25PM

Registered Member #23375

Joined: Sat Oct 31 2009, 06:14AM

Posts: 5
Thanked 1 time in 1 posts

Here is sechematic, please any one provide me asembly code for communicate with 8255 using 89c51!
thanks!
sorry!, My english is not good!

[ Edited Sat Oct 31 2009, 08:18PM ]

Ajay Bhargav

Sun Nov 01 2009, 05:56AM

Rickey's World Admin

Registered Member #1

Joined: Fri Feb 24 2006, 04:56AM

Posts: 7468
Thanked 1320 times in 1244 posts

First of all, please try not to create multiple threads.

Now, 8255 has got 4 registers, which can be selected with combination of A0 and A1 address pins of 8255.
00 = PortA
01 = PortB
10 = PortC
11 = Control register.

you need to configure control register to control the IO ports.

From the circuit diagram you posted address will be like this
E000 = PortA
E001 = PortB
E002 = PortC
E003 = Control Register

do access these registers you can use MOVX instruction. user DPTR to point to this address.

www.rickeyworld.info
If you feel satisfied with the user's forum reply please click on the thank button.

Obey forum rules!
Respect others!

This post has been thanked 1 time

vanbayhoang

vanbayhoang

Sun Nov 01 2009, 06:21AM

Registered Member #23375

Joined: Sat Oct 31 2009, 06:14AM

Posts: 5
Thanked 1 time in 1 posts

thanks! you have code asembly beforehand ( you writed), send your code to me.
sorry!, My english is not good!

Ajay Bhargav

Sun Nov 01 2009, 10:22AM

Rickey's World Admin

Registered Member #1

Joined: Fri Feb 24 2006, 04:56AM

Posts: 7468
Thanked 1320 times in 1244 posts

well i do not have the code with me. but its simple.

CODE:

mov DPTR, #0E000H

mov a,#54H ;data to move

movx DPTR,a ;send data to register 0E000

the above code is just example of how to move data to 8255 register. so configure 8255 in IO mode and then use it as normal IO port.

if you are new to 8255 then check this page
http://www.thesatya.com/8255.html
also see datasheet for more info.

www.rickeyworld.info
If you feel satisfied with the user's forum reply please click on the thank button.

Obey forum rules!
Respect others!

This post has been thanked 1 time

vanbayhoang

DavesGarage

Sun Nov 01 2009, 09:30PM

Registered Member #14254

Joined: Tue Jan 20 2009, 08:14AM

Posts: 618
Thanked 115 times in 111 posts

You better check that address again, Dude... I see 0x1XXX for the address base.

In other words 0x1000, 0x1010, 0x1020...0x1FF0 all will address Port A
and 0x1001, 0x1011, 0x1021...0x1FF1 all will address Port B
and so on...

Those inverters make this so...

-Dave
"Basic research is what I am doing when I don't know what I am doing"