Depends on your application. Is this a home/hobby project or commercial/industrial application?
What are the consequences of corrupt transmission?

Try 2m @ 4800 baud over two twisted pairs, i.e. TX/GND and RX/GND.

It's consumer Electronics Product for home.


Thanks !!!

 

Can you could do some experiments with 2 meters of twisted pair cable between a TTL transmitter and receiver and see how it works?
You may have to add a resistor in series with the transmitter output to control the rise-time and thus the ringing at the receiver end.

What "TTL" circuits are you using (3.3V is not standard TTL)?

Ok, will do as per your suggestions.
My logic level is 3.3V for MCU.

 

My logic level is 3.3V for MCU.

Okay.
But what logic family are you using?

 

I meant was -

Could it be possible that TTL UART will work at 2 meter distance at lower baud rate.

May be anyone had same experience and their thought definitely gonna help me.

Yes their are way to do this ...

1. Using RS232 transceiver IC at both end (both boards) could cost of 2 transreciver ICs.
2. RS485 differential mode communication can do the same Job and they can also cost if transreceiver ICs.

Only cost effectevie solution was TTL UART and if this is not going to work , I have to go with either any of above solutions.

Thanks to all for your reply !!!

It's easy to to add RS232 Serial to TTL with a small 5VDC daughterboard, if you're using 5VDC.

Or use a couple of transistors and drive your signals yourself, if you want to stay with TTL.

 

Does your microcontroller have an I2C (inter-integrated circuit, also called I squared C. does anybody know how to do superscript in this editor?)
I2C can do 10Kbaud at 10meters. It is not the same protocol as RS232 but its purpose is to communicate between devices in close proximity. If both ends have I2C capability then it wouldn't be a problem to go 2 meters. You could also use SPI (serial peripheral interface) but it is a three wire interface. !2C is a two wire interface, a data wire and a clock wire. Data can only be half duplex (one direction at a time).

 

Okay.
But what logic family are you using?

It's Microcontroller STM32F series

 

It's Microcontroller STM32F series

That’s your Microcontroller. A logic family is one of the following (not all inclusive and includes logic families that are rarely used currently)

• DL
• DTL
• RTL
• ECL
• TTL
• CMOS

...and may be further classified as tu feature, such as high speed, etc.

 

If you find you have to buffer the lines without going the full RSxxx route , consider something like buffers in the Tiny Logic families:
https://www.mouser.com/datasheet/2/916/74LVC2G241-1319835.pdf
The link is just an example but easier than rolling your own.

 

If you find you have to buffer the lines without going the full RSxxx route , consider something like buffers in the Tiny Logic families:
https://www.mouser.com/datasheet/2/916/74LVC2G241-1319835.pdf
The link is just an example but easier than rolling your own.

Thank for your reply .

What is pros & cons of putting Buffer in UART line.
If we put buffer how it affect the signals.

Thanks !!!

 

Thank you all for your overwhelming support.

What is basic reason for putting Transreciever ICs in UART communication.
How it impact the signals.
What is pros and cons.

Regards,

 

The main reason is signal reliability and quality with resistance to outside EMI etc.
Max.

 

The main reason is signal reliability and quality with resistance to outside EMI etc.
Max.

That's probably one reason.

but how does it justify technically.


Regards,

 

but how does it justify technically.

Your product works. There are less returns. Your company gets a good reputation. People buy your product.

 

The main reason is signal reliability and quality with resistance to outside EMI etc.

That's probably one reason. but how does it justify technically.

That IS the technical justification. Using an appropriate line driver and receiver suited to the operating environment minimizes signal distortion and bit errors and reduces susceptibility to interference from outside noise or other signals. It can also protect expensive system components (like your MCU) from damage or disruption from outside events such as electrostatic discharge.

What more justification do you need?

 

Your product works. There are less returns. Your company gets a good reputation. People buy your product.

Political Answer ???

Thanks

 

Political Answer ???

Thanks

Are you building one of a kind for your own use or are you planning to produce this item for sale?

What are the consequences of failure?

 

That IS the technical justification. Using an appropriate line driver and receiver suited to the operating environment minimizes signal distortion and bit errors and reduces susceptibility to interference from outside noise or other signals. It can also protect expensive system components (like your MCU) from damage or disruption from outside events such as electrostatic discharge.

What more justification do you need?

That's correct and I do agree with all.
Probably I used incorrect word " justification" . I hearty sorry if it was inappropriate.

My intention was to ask about technical specifications. Means if I use transceiver IC it gives low output impedance to avoid signal distortion and likewise ....???

Anyway thanks to everyone your overwhelming support.

 

Are you building one of a kind for your own use or are you planning to produce this item for sale?

What are the consequences of failure?

It's not a hobby project .
It's for my customer in consumer electronics domain.
I raised this question to mitigate the risk and should able to give justification for any decision.

Thanks.

 

@mishra87
If you're engineering a solution for a customer, then you should understand the use of your tools. Your uart is a means to get a communication signal out of your MCU, as is any pin. That's it. Your MCU has a maximum current limit across all pins.

As such, a smart engineer uses as little current as necessary for all uses in his MCUs in order to support the greatest number of signal pins available for simultaneous use and keep the MCU itself relatively cool.

If you want to use TTL, consider driving a transistor with the TTL signals, because the transistor(s) can switch greater voltages and currents without creating undue demand on the MCU. Use UTP, and you can easily drive a 'TTL' signal 6 feet or more, even in relatively noise environments. You can capture the signal using a 4N35 plus a couple of other components for isolation.

There is nothing complicated about communication. People make it more difficult than it is.

 

It's Microcontroller STM32F series

So you want to drive the line directly from the micro?
That's generally not a good idea. You should have some sort of buffer circuit between the micro and the line.
If you need to add a circuit for this, than just use an RS-232 chip.