I used MAX232CPE without any capacitor and power supply is tied.Then I tied the TX of comm port to one pins the the RX of the comm port to another pins of MAX232.Next transmit data to comm port.But i am confusing that I can receive data exactly when TX and RX is tied any pin of MAX232
I have tested MAX232 it is good.Would you tell me is this is true?Or there something wrong here?
At first I had connected all components as the datasheet and i found that I only need tied TX to one pins and RX to another pins of max232 to transmit data without power supply.
Then in order to debug this circuit i checked by removing every component step by step.Finally, when all caps and power is removed, I sitll received the data exactly.
It seem that all pins of max232 is connectted to each other without power and resulting in TX and RX is connected to each other.
It make me confuse if it is true for this chip or not.Previously I thought the chip is blown but when i checked it under this the following guide all results are relatively right.
"Power up the MAX232 and check voltage across supply pins to insure correct voltage input.
The following two tests check each "TTL in - RS232 out" converter.
Put 0 volts into pins 10 and 11, then check pins 7 and 14. Should have about 10 volts output on each.
Put 5 volts into pins 10 and 11, then check pins 7 and 14 again. Should have about -10 volts output on each.
If that succeeded, then check each "RS232 in - TTL out" converter. Connect pin 7 to pin8. Connect pin 13 to pin 14. This will be a "loopback test".
Put 0 volts into pins 10 and 11, then check pins 9 and 12. Should have about .6 volts output.
Put 5 volts into pins 10 and 11, then check pins 9 and 12 again. Should have about 4.5 volts output."
Therefore I it make me confuse that chip is work or not.
I have used the same IC many times and so far have not had a problem if it is configured correctly with the recommended capacitors?
It is a fairly straight forward IC to use and test?
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