That would depend entirely on the chosen baud rate, the logic technology being used (TTL, LSTTL, CMOS, etc.) and how noisy the electrical operating environment is; so it's impossible to give you a specific maximum distance.What could be the maximum achievable length for TTL UART communication between two boards without using transreciever IC.
WHICH standard baud rate??? 75 bits/second? 300? 1200? 9600? 115K? I hope you realize that just saying "standard baud rate" doesn't tell anyone anything.Assuming standard baud rate for communication.
Baud rate ...at which TTL UART can communicate effectively without any signal distorition.What is 'standard' baud rate - 300? 38400? It makes a lot of difference.
Quite Good information and gonna help me.I think the main reason why we're having difficulty answering your question with certainty is that for any distance at all, good design practice demands some sort of driver / interface to adapt the TTL logic signal to driving over distance. TTL is just not designed for that. It is not uncommon to see drivers / buffers in larger systems in TTL to TTL lines. My personal experience with raw TTL over some feet of distance back in the day was unsatisfactory.
Here's some info for RS-232 showing distance vs. baud rate:
https://www.lammertbies.nl/comm/info/RS-232_specs.html
For longer hauls consider RS422 / RS485. These use differential signalling and can be used in point to point connections like your UART. I personally use them for any appreciable distance.
http://www.rs485.com/rs485spec.html
Good luck!
TTL level at both end 3V3.Try providing the information asked. Your last post does not add much to the characterization of the problem.
An example of a better formed question is: https://electronics.stackexchange.com/questions/31949/maximum-cable-length-for-3-3v-uart-signals
So, not only the data rate is specified, but also the TTL voltage levels and the media where the signals will travel.
As you can also tell from the ensuing discussion, there is no umbrella answer for this question - it will demand some calculation and experimentation due to several factors (some uncontrollable) already mentioned above, such as the output strength of the pins driving the lines, the sensitivity and noise immunity of the input pins listening to the lines, surrounding environment (noise, transients), quality of cables and connectors (cross talk, attenuation), among others.
I guess , May be tried to market their own Forum.Try providing the information asked. Your last post does not add much to the characterization of the problem.
An example of a better formed question is: https://electronics.stackexchange.com/questions/31949/maximum-cable-length-for-3-3v-uart-signals
So, not only the data rate is specified, but also the TTL voltage levels and the media where the signals will travel.
As you can also tell from the ensuing discussion, there is no umbrella answer for this question - it will demand some calculation and experimentation due to several factors (some uncontrollable) already mentioned above, such as the output strength of the pins driving the lines, the sensitivity and noise immunity of the input pins listening to the lines, surrounding environment (noise, transients), quality of cables and connectors (cross talk, attenuation), among others.
What do you mean by that?I guess , May be tried to market their own Forum.
Thanks for your valuable information.You need to tell us your baud and/or cable length.
Look at RS-232 specifications:
RS-232 drivers employ circuits with controlled rise times.
If you want to go straight TTL here are some tips:
1) use CMOS ICs
2) reduce your baud
3) control the rise times
4) use twisted pairs
5) keep the cable length to a minimum
If you are still seeking a hard and fast answer, the answer is 3 ft (1m) @ 9600 baud.
by Aaron Carman
by Duane Benson
by Duane Benson