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Difference between RS232 to UART and USB to UART

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Hi everyone,

I am facing with a problem about changing DB9 port to USB port to adapt to new computer generation.

I download an application that has a Graphic user interface was written on Windows XP, use DB9 port connect to a board has a MAX232 IC to convert signal from RS232 to UART to communication with MCU with diagram:

PC -- DB9 cable -- RS232 to UART -- MCU.

My computer running windows 8, which does not have DB9 port, so I bought a board that convert USB to TTL (uart). So now my diagram is:

PC --- USB cable -- USB to TTL board --- MCU.

With my connection (using USB to TTL), I can not use the GUI to read or write signal because the GUI waiting for a "\r" ascii 13 or CR to parse data. I can confirm that because I can use a serial port software such as putty to type the command and communication with the board.

So my question is when I change RS232 to USB, will my signal be changed? if yes, could you suggest for me a solution?

Thank you so much!


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For an inexpensive, less complex solution you may want to look at something like the Cypress Semiconductor CY8Ckit-049-42xx. While this is actually a inexpensive development board for their PSoC line of MCUs, it has a detachable USB to Serial(TTL level signals) section. They also offer software to configure the serial parameters and it even supports I2C and SPI. Board costs about $4.00. Here is some info on the board:





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