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UART Module API Manual

Overview

K230 integrates five UART (Universal Asynchronous Receiver/Transmitter) hardware modules internally, where UART0 is occupied by the small-core SH, UART3 is occupied by the large-core SH, and the remaining UART1, UART2, and UART4 are available for users. For UART I/O configuration, refer to the IOMUX module.

Warning

Before physically connecting UART pins, you must confirm whether the corresponding I/O domain of the development board uses 1.8 V or 3.3 V to ensure external device level matching. Do not connect 5 V UART signals. Do not use the low-quality CH340G modules shown in the documentation. For wiring requirements, prohibited module images, and voltage check methods, see Serial Port Level and Adapter Module Safety.

API Introduction

The UART class is located in the machine module.

Example Code

from machine import UART

# Configure UART1: baud rate 115200, 8 data bits, no parity, 1 stop bit
u1 = UART(UART.UART1, baudrate=115200, bits=UART.EIGHTBITS, parity=UART.PARITY_NONE, stop=UART.STOPBITS_ONE)

# Write data to UART
u1.write("UART1 test")

# Read data from UART
r = u1.read()

# Read one line of data
r = u1.readline()

# Read data into a byte buffer
b = bytearray(8)
r = u1.readinto(b)

# Release UART resources
u1.deinit()

Constructor

uart = UART(id, baudrate=115200, bits=UART.EIGHTBITS, parity=UART.PARITY_NONE, stop=UART.STOPBITS_ONE, timeout = 0)

Parameters

• id: UART module number, valid values are UART1, UART2, UART4.

• baudrate: UART baud rate, optional parameter, default value is 115200.

• bits: number of data bits per character, valid values are FIVEBITS, SIXBITS, SEVENBITS, EIGHTBITS, optional parameter, default value is EIGHTBITS.

• parity: parity check, valid values are PARITY_NONE, PARITY_ODD, PARITY_EVEN, optional parameter, default value is PARITY_NONE.

• stop: number of stop bits, valid values are STOPBITS_ONE, STOPBITS_TWO, optional parameter, default value is STOPBITS_ONE.

• timeout: data read timeout, in ms

init Method

UART.init(baudrate=115200, bits=UART.EIGHTBITS, parity=UART.PARITY_NONE, stop=UART.STOPBITS_ONE)

Configure UART parameters.

Parameters

Refer to the constructor.

Return Value

None

read Method

UART.read([nbytes])

Read characters. If nbytes is specified, at most that many bytes are read; otherwise, as much data as possible is read.

Parameters

• nbytes: maximum number of bytes to read, optional parameter.

Return Value

Returns a bytes object containing the read bytes.

readline Method

UART.readline()

Read one line of data, ending with a newline character.

Parameters

None

Return Value

Returns a bytes object containing the read bytes.

readinto Method

UART.readinto(buf[, nbytes])

Read bytes into buf. If nbytes is specified, at most that many bytes are read; otherwise, at most len(buf) bytes are read.

Parameters

• buf: a buffer object.

• nbytes: maximum number of bytes to read, optional parameter.

Return Value

Returns the number of bytes read and stored in buf.

write Method

UART.write(buf)

Write a byte buffer to the UART.

Parameters

• buf: a buffer object.

Return Value

Returns the number of bytes written.

deinit Method

UART.deinit()

Release UART resources.

Parameters

None

Return Value

None