[SOLVED] How to connect 4 8051 using UART and AT89S52?

[torana]

hello,

i am trying to connect three 4Nos 8051 each other by UART. AT89s52 is my micro controller.
my controller is having one UART. for communication i am using MAX 232 IC.
i know that on this is a point-to-point communication.
is there any way that i can connect 4 micro controller.
in my place only AT89C51/C52/S51/S52 available. so i have to select micro controller from these.
MAX 232 IC is also available. So Pls help.

 

[shamikrudra]

Re: problem in 8051 UART

Your question is not very clear. are you want to connect 3 89s52 with each other and 1 89s52 to control other 3? or you want to connect it to PC serial port?
if you are not using PC serial port for connection, you don't need max232. I think there is a better way to connect 4 controllers is IIC protocol. search it on google.
where are you staying?

 

[torana]

Re: problem in 8051 UART

Your question is not very clear. are you want to connect 3 89s52 with each other and 1 89s52 to control other 3? or you want to connect it to PC serial port?
if you are not using PC serial port for connection, you don't need max232. I think there is a better way to connect 4 controllers is IIC protocol. search it on google.
where are you staying?

Thank you. i want to communicate from first mcu to other three mcu. and my distance will be around 7 meter. I think it is possible by RS485, but i donot have knowledge on rs485. i am very friendly with RS232. pls follow two FIG.1 and FIG.2. i just want to connect 4 mcu.

i am from orissa

 

[js]

Re: problem in 8051 UART

if you only need one master and 3 slaves then figure1 and if you need low speed baude rate (up to 9600baud) you can wire direct with resistor loading!
If you havan't noise enviroment there will work without problems!

 

[shamikrudra]

Re: problem in 8051 UART

I²C - Wikipedia, the free encyclopedia
hope this link will help you.

 

[mehta.vishal.360]

Re: problem in 8051 UART

You can use null modem connection to connect the controllers or else you can try to do SPI... search about SPI and let me knw....