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Communication protocols

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Member level 3
Sep 1, 2012
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Hello Everyone!
I am having this confusion between communication protocols. I have worked on them a lot on hardware but still I am not able to completely grasp the concept. What is the difference between TTL, Serial Output, RS232 output, CMOS? which one needs a max232 circuit while interfacing with atmega16? what exactly is the protocol of atmega16? This might seem a bit silly but Please tell me the very basics.. its all mixed
Thanks in advance

TTL is technology which made the circuits. This directive informs that your system working on 5volt maximum and 3.3 volt minimum
Serial output is general term for data sending and receiving
RS232 is a serial protocol. This protocol need some voltage translator because it is designed to work with 12 / -12 voltages or some other variation in voltage depend on system manufacture.
Cmos is another technology of made circuits. It working with voltages from 5 volts up to 16 volts.
The atmega16 has the RS232 protocol inside the IC but it is working with 5volt and 0 volts. Because you are not know in which system it will be connected you must design a voltage translator to be sure that your system it will be working fine.

I am working on RFID ID20 which says that it works on TTL and RS232. Can I connect it with Atmega16 directly or I have to use a translator like max232? why or why not? please clarify

if you mean the product from sparkfun yes you could connected directly with the atmega16. In other case you must see the datasheet from the manufacture.

Ok thanks a lot for that!
Do you have idea about rfid id20?

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