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Serial Port logic inverted
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Anonymous
Hi everyone,
I was using the serial port and now I need to invert the logic of uart communication, I mean if i send the data 0b11000111 then the logic level in usb converter TX must be 0b00111000. How I can do this? thanks for your help.
Best regards
Developer technologies | C#
{count} votes
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AgaveJoe 30,126 Reputation points2021-07-28T22:36:26.227+00:00 Use the C# the compliment operator ~ in your software to invert the bits before sending the data. Otherwise, connect a physical inverter (7404) to the Tx (pin 3) on the serial port.
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Anonymous
2021-07-28T22:44:18.33+00:00 @AgaveJoe thanks for your reply. I forgot to mention but I also need inverted logic for start, parity and stop bits while iddle state is in high level. Your reply apply for this case too?
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AgaveJoe 30,126 Reputation points
2021-07-28T23:42:10.16+00:00 I forgot to mention but I also need inverted logic for start, parity and stop bits while iddle state is in high level. Your reply apply for this case too?
Wire in a 7404 to physically invert the Tx pin assuming TTL level voltages. Otherwise, read the documentation that comes with your unknown hardware. Are you bit banging a GPIo? Is this a TTL to RS232 question?
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Anonymous
2021-07-29T16:37:09.31+00:00 @AgaveJoe thanks for your reply. About hardware, I can't add new componentes, I can only work with FTDI alone. In this way your reply about bitbanging give me a good clue to move forward. I will try the FTD2XX DLL.
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Anonymous
2021-08-10T05:21:19.14+00:00 Hi @Anonymous ,
Is there any update, have you resolve the issue. please let me know if there is anything that I can help here.
Best regards,
Zhanglong -
Anonymous
2021-08-10T18:51:04.543+00:00 @Anonymous yes, I already solved this problem. I was using a usb adapter to communicate via SDI-12 and this adapter had inside a FTDI. In the eeprom of FTDI I could invert the logic and using FTDI libraries for .net I could generate break signals to generate SDI12 communication. Regardlees, thanks for your help.
Best Regards
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رضا جافری 1,296 Reputation points2021-08-10T21:11:22.057+00:00 If I write a method (of course, a method in C #) to invert your 10 characters, will your problem be solved?
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Anonymous
2021-08-10T21:45:04.037+00:00 Hi @RezaJafery, the problem I had was already solved using FTDI libraries. In particular, I needed to implement SDI12 protocol with a usb to uart adapter but this question was posted when I knew a little about it and focused my problem first on invert signals. Now I know how to use the FTDI adapter. Also I don't know how finish or mark this question as solved.
Best Regards
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Timon Yang-MSFT 9,606 Reputation points2021-08-11T06:03:26.22+00:00 @Anonymous
It seems that AgaveJoe's comment provided you with an idea, and then you solved the problem yourself.
If it is convenient for you, you can post your solution as an answer and then accept it. This will enable people who encounter similar problems in the future to quickly find feasible solutions.
Have a nice day.
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