Hi...i want to communicate usart communication between 2 different microcontrollers...what are the hardware conections we have to give for communicating between 2 different microcontrollers...and how to take care in the software part like baudrate must be same for both controllers...? please suggest as i am new to microcontroller programming..

Thanks in Advance

 

i have done a search on net but i am not able to find any thing for communication between 2 different controllers....

 

What is the question?
Once you set the baud rates to be the same you should not have a problem.
You have not specified the model numbers of the microcontrollers.

 

can u help me in hardware part...how to give connections...do we need any special ic for connecting between 2 mcu other than TTL...

 

No. Connect RXD of one MCU to TXD of the other MCU.

 

kk...thnx for your reply..

 

one more thing i want to clarify both controllers are of different voltages...will there be any issue in transmitting data if voltages are different...

 

Use MAX232 level shifters on both mcu and that should solve the problem.

Allen

 

Specify your voltages. You can adapt for different voltages.

Also, learn to communicate. Why does it take two posts to get your information across?

 

sorry for this..from next time i wont repeat it again.....one mcu is operating at 3.3v and the other mcu at 1.8v

 

If these 2 micros are on the same board then something like the MAX232 would be overkill. All you'd need is some sort of level shifter between the voltage domains, something like a NLSX4302E 2-Bit 20 Mb/s Dual-Supply Level Translator may work better with less parts.

However, these are all very modern devices and may only be available in surface mount packages.

 

To reduce a 3.3v TXD signal to suit 1.8v RXD input, simply use a voltage divider and/or a diode clamp.

To boost a 1.8v TXD signal for a 3.3v RXD input, use a non-inverting transistor buffer. A simple solution such as a pullup resistor might work.

 

Here's the level converter using mosfet and resistors...

http://www.sparkfun.com/datasheets/BreakoutBoards/Level-Converter-v10.pdf

you can buy it pre-made from sparkfun

https://www.sparkfun.com/products/8745

Allen

 

ernie,absf,mrchips thnx a lot for your reply..i will try this and update here