How to use 485 communication with MicroPython

zhaoqx

How to use 485 communication with MicroPython [Copy link]

 

 Is there any useful one? Please give me some advice.

dcexpert

The usage is the same as the general serial port.

zhaoqx

No library found to set the enable end

szl123456

How does this uart transmit 485 signals? Do I need a Modbus?

dcexpert

Compared with the ordinary 485 serial port, it has an additional transmit and receive enable, which can be controlled by a GPIO.

dcexpert

szl123456 posted on 2019-4-6 21:02 How can this uart transmit 485 signals? Do I need to make a Modbus?

The modbus seems to be available on github, you can go and have a look

Ediwin

dcexpert posted on 2019-4-8 08:39 Compared with the ordinary 485 and the serial port, it has an additional transmit and receive enable, and you can control it with a GPIO.

With the MAX13487EESA RS485 chip, you don't have to worry about enabling the send and receive function. It is compatible with both 3.3V and 5V serial ports.

dcexpert

Ediwin published on 2019-11-14 15:13 With the MAX13487EESA RS485 chip, you don't have to worry about the issue of enabling and disabling the send and receive functions. It is also compatible with 3.3V and 5V serial ports

Of course it is possible to use a chip that automatically controls the transmission and reception.

Ediwin

dcexpert posted on 2019-11-14 15:14 Of course it is possible to use a chip that automatically controls the transmission and reception.

dcexpert, does the Pyboard's serial port data receiving buffer have a clearing function?

dcexpert

Ediwin posted on 2019-11-14 15:20 dcexpert, does the Pyboard serial port data receiving buffer have a clearing function?

Micropython has a serial port buffer (the size can be defined by yourself) to avoid data loss. You can use any() to determine whether there is data in the buffer. The serial port buffer content can be read through read(). When all the data is read, it is cleared.

Ediwin

dcexpert posted on 2019-11-14 15:23 Micropython has a serial port buffer (the size can be defined by yourself) to avoid data loss. Use any() to determine the buffer...

Dcexpert, does MicroPython have a library similar to https://pypi.org/project/crcmod/?

mlhorizon

I added a small board for converting ttl to 485, which is quite easy to implement, and there is also a modbus library.