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UART
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**API Documents**
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**Constructors**
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| **UART(**\ *unit*\ [optional]\ *, baudrate*\ [optional]\ *, databits*\ [optional]\ *, stopbit*\ [optional]\ *, paritybit*\ [optional]\ *, timeout*\ [optional]\ *, tx_pin*\ [required]\ *, rx_pin*\ [required]\ **)**
| Create a UART object associated with the given tx and rx pins and configure it using other parameters. This allows you to then read/write uart signal on the pins.

-  ``unit``: The unit ID, either 0 or 3
-  ``baudrate``: 115200 is the recommended baudrate on ameba
-  ``databits``: the number of bits for data bits, usually 7 or 8 bits
-  ``stopbits``: the number of stop bits, usually 1 or 1.5 or 2 bits
-  ``paritybit``: for parity check, usually none, odd or even
-  ``timeout``: how long uart wait before its timeout (in milliseconds)
-  ``tx_pin``: the transmitter pin, connect the rx pin of the receiver
-  ``rx_pin``: the receiver pin, connect to tx pin of the transmitter

.. note::  
   Not all parameters are required, thus MicroPython will assume its default value once left blank, here are the default values for each optional parameter:

.. table:: 
   :align: center

   ========= =============
   Parameter Default Value
   ========= =============
   Unit      0
   Baudrate  115200
   Databits  8
   Stopbits  1
   Paritybit 0
   Timeout   10 (ms)
   ========= =============


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**Methods**
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| **UART.init()**
| This method initializes and configures the UART.

| **UART.read(**\ *length*\ [optional]\ **)**
| This method reads the data received in UART buffer.

-  **length:** the length of the data to receive

| **UART.readline()**
| This method is similar to read(), but read a line ending with a newline character.

| **UART.write(**\ *buffer*\ [require]\ **)**
| This method sends the buffer of bytes to the bus and returns the number of bytes written.

- **buffer**: data buffer that can be a string, an integer or other data types

| **UART.irq_enable(**\ *bool*\ [optional]\ **)**
| This method works in 2 way:

1. Check the status of uart irq when NOT passing any argument, and it will return True if irq is enabled, False if disabled
2. Enable/disable uart irq handler by passing True or False as bool

| **UART.irq_handler(**\ *function*\ [required]\ **)**
| Passing the python handler to uart irq so that it will be triggered when an UART event occurs.

- **function:** a function defined in python or a lambda function