When I plug the device into the serial port of my computer I can read the data from a terminal window. That is precisely what has me so confused. I know the RS232 interface arduino shield works, and I know that the device works fine with my computer, so why doesn't it play nicely with the arduino?

The UART (Universal asynchronous receiver/transmitter) module allows configuration of and communication over the UART serial port.

The default setup for the uart is controlled by build-time settings. The default rate is 115,200 bps. In addition, auto-baudrate detection is enabled for the first two minutesafter platform boot. This will cause a switch to the correct baud rate once a few characters are received. Auto-baudrate detection is disabled when uart.setup is called.

Important

Although there are two UARTs(0 and 1) available to NodeMCU, UART 1 is not capable of receiving data and is therefore transmit only.

uart.alt()¶

Change UART pin assignment.

Syntax¶

uart.alt(on)

Parameters¶

on

• 0 for standard pins
• 1 to use alternate pins GPIO13 and GPIO15

Returns¶

nil

uart.on()¶

Sets the callback function to handle UART events.

Currently only the 'data' event is supported.

Note

Due to limitations of the ESP8266, only UART 0 is capable of receiving data. Serial killers mbti chart.

Syntax¶

uart.on(method, [number/end_char], [function], [run_input])

Parameters¶

• method 'data', data has been received on the UART
• number/end_char
  • if n=0, will receive every char in buffer
  • if n<255, the callback is called when n chars are received
  • if one char 'c', the callback will be called when 'c' is encountered, or max n=255 received
• function callback function, event 'data' has a callback like this: function(data) end
• run_input 0 or 1. If 0, input from UART will not go into Lua interpreter, can accept binary data. If 1, input from UART will go into Lua interpreter, and run.

To unregister the callback, provide only the 'data' parameter.

Returns¶

nil

Example¶

uart.setup()¶

(Re-)configures the communication parameters of the UART.

Note

Bytes sent to the UART can get lost if this function re-configures the UART while reception is in progress.

Syntax¶

uart.setup(id, baud, databits, parity, stopbits[, echo])

Parameters¶

• id UART id (0 or 1).
• baud one of 300, 600, 1200, 2400, 4800, 9600, 19200, 31250, 38400, 57600, 74880, 115200, 230400, 256000, 460800, 921600, 1843200, 3686400
• databits one of 5, 6, 7, 8
• parityuart.PARITY_NONE, uart.PARITY_ODD, or uart.PARITY_EVEN
• stopbitsuart.STOPBITS_1, uart.STOPBITS_1_5, or uart.STOPBITS_2
• echo if 0, disable echo, otherwise enable echo (default if omitted)

Returns¶

configured baud rate (number)

Example¶

uart.getconfig()¶

Returns the current configuration parameters of the UART.

Syntax¶

uart.getconfig(id)

Parameters¶

• id UART id (0 or 1).

Returns¶

Four values as follows:

• baud one of 300, 600, 1200, 2400, 4800, 9600, 19200, 38400, 57600, 74880, 115200, 230400, 256000, 460800, 921600, 1843200, 3686400
• databits one of 5, 6, 7, 8
• parityuart.PARITY_NONE, uart.PARITY_ODD, or uart.PARITY_EVEN
• stopbitsuart.STOPBITS_1, uart.STOPBITS_1_5, or uart.STOPBITS_2

Example¶

uart.write()¶

Write string or byte to the UART.

Syntax¶

uart.write(id, data1 [, data2, ..])

Parameters¶

• id UART id (0 or 1).
• data1.. string or byte to send via UART

Returns¶

nil

Example¶