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Serial Communication 3.1.11

WARNING

Due to reasons such as unstable communication, errors may occur. In most cases, it is necessary to use the error handling mechanism to catch errors and prevent abnormal exits.

Open Serial Port Device

com = serial.open(path)

By default, it uses a baud rate of 115200, 8 data bits, 1 stop bit, and no parity. Please contact us if you need to change these settings.

  • Parameters
    • path: Serial port device address.

Returns a serial port instance or throws an error.

Set Timeout

com:set_timeout(timeout)
  • Parameters
    • timeout: Timeout in milliseconds (ms). Default is 800ms.

Set Baud Rate

com:set_baud_rate(baud_rate)

Set the serial port baud rate.

  • Parameters
    • baud_rate: Serial port baud rate. Default is 115200.

Returns nothing or throws a connection error.

Set Parity

com:set_parity(parity)

Set the parity bit.

  • Parameters
    • parity: Parity bit (None: no parity; Odd: odd parity; Even: even parity). Default is no parity.

Returns nothing or throws a connection error.

Send Data

com:write(data)

Send a u8 array via serial port.

  • Parameters
    • data: u8 array to be sent.

Returns nothing or throws a connection error.

Receive Data

data = com:read(len)

Receive a u8 array via serial port.

  • Parameters
    • len: Maximum buffer length for a single reception, can be empty, default is 64 bytes.

Returns a u8 array or throws a connection error.

Example

local com1 = serial.open("/dev/ttyS1")
com1:set_timeout(200)
com1:set_baud_rate(9600)

local str = "123"
com1:write({string.byte(str, 1, #str)}) -- Send string
com1:write({0x01, 0x02, 0x03}) -- Send HEX

-- Read from serial port, using pcall to catch errors
success, result = pcall(function() return com1:read() end)
if success then
  print(result) -- Print HEX
  print(string.char(table.unpack(result))) -- Print string
else
  print("Error: ", result)
end

-- Read from serial port, since errors are not caught, the task will exit abnormally when an error occurs
local data = com1:read()
print(data) -- Print HEX
print(string.char(table.unpack(data))) -- Print string