Serial port part add 485 chip DE pin control

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Joined: Sat May 06, 2023 2:00 pm

Serial port part add 485 chip DE pin control

Post by SHIPC »

In industrial control, we often use 485,485 to receive or send depending on the 485 chip DE pin. Now whether you can add automatic flow control function in the code, to achieve 485 automatic manipulation 3 control. In the manual of STM32G070RBT6, I found these words: They provide hardware management of the CTS, RTS and RS485 DE signals,

RS485 Driver Enable
The driver enable feature is enabled by setting bit DEM in the USART CR3 control register This allows the user to activate the external transceiver controlthrough the DE(Driver Enable) signal.The assertion time is the time between the activation of the DE signal and the beginning of the START bit.It is programmed using the DEAT[4:0] bit fields in the UsART CR1 control reaister. The de-assertion time is the time between the end of the last stop bit, in a transmitted message, and the de-activation of the DE signal.It is programmed using the DEDT4:0bit fields in the UsART CR1 contro register. The polarity of the DE siqnal can be confiqured using the DEP bit in the USART CR3 controreqister.
In UsArt the DEAT and DEDT are expressed in sample time units (1/8 or 1/16 bit duration depending on the oversampling rate).
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