machine.UART

The uart module is mainly used to drive the asynchronous serial port on the development board, and uart can be freely configured. The k210 has a total of 3 uarts, and each uart can perform free pin mapping.

1. Construction

1.1. Pin mapping

Before using uart, we need to use fm to map and manage the chip pins. As shown below, set PIN10 as the sending pin of uart2 and PIN11 as the receiving pin of uart2

fm.register (board_info.PIN10, fm.fpioa.UART2_TX)
fm.register (board_info.PIN11, fm.fpioa.UART2_RX)

1.2. Constructor

uart = machine.UART (uart, baudrate, bits, parity, stop, timeout, read_buf_len)

Create a new UART object with the specified parameters

parameters

• uart UART number, use the specified UART, you can complete it by pressing the machine key withmachine.UART.
• baudrate: UART baud rate
• bits: UART data width, support5/6/7 / 8 (the default serial port used by REPL (UARTHS) only supports 8-bit mode), default 8
• parity: parity bit, supportsNone, machine.UART.PARITY_ODD,machine.UART.PARITY_EVEN (the default serial port used by REPL (UARTHS) only supports None), default None
• stop: stop bit, supports1, 1.5,2, default 1
• timeout: serial port receive timeout
• read_buf_len: Serial port receive buffer. The serial port receives data through interrupt. If the buffer is full, it will automatically stop receiving data.

return value

• UART object

2. Method

2.1. init

Used to initialize uart, usually already initialized when constructing the object, here is used to re-initialize uart

uart.init (baudrate, bits, parity, stop, timeout, read_buf_len)

parameters

Same constructor but does not require the first UART number

return value

no

2.2. read

Used to read data from serial buffer

uart.read (num)

parameters

• num: the number of bytes read, generally fill the buffer size, if the number of data in the buffer is not as large asnum, then only the remaining data in the buffer will be returned

return value

• bytes data

2.3. readline

Yihang for reading serial buffered data

uart.readline (num)

• num: number of rows read

return value

• bytes data

2.4. write

Used to send data using the serial port

uart.write (buf)

parameters

• buf: need to send data

return value

• Amount of data written

2.5. deinit

Unregister UART hardware and free up resources

UART.deinit ()

parameters

no

return value

no

2.6. repl_uart ()

Get serial object for REPL

return value

Serial object for REPL, default initialization bit 115200 8 N 1

3. Examples

3.1. Routine 1

Before running mileage, please make sure PIN15 is connected toPIN10 and PIN17 is connected toPIN9

After running the program, you can see the print information of baudrate: 115200 bits: 8 parity: 0 stop: 0 --- check Successfully in the terminal

from fpioa_manager import fm
from machine import UART
fm.register (board_info.PIN15, fm.fpioa.UART1_TX)
fm.register (board_info.PIN17, fm.fpioa.UART1_RX)
fm.register (board_info.PIN9, fm.fpioa.UART2_TX)
fm.register (board_info.PIN10, fm.fpioa.UART2_RX)
uart_A = UART (UART.UART1, 115200, 8, None, 1, timeout = 1000, read_buf_len = 4096)
uart_B = UART (UART.UART2, 115200, 8, None, 1, timeout = 1000, read_buf_len = 4096)
write_str = 'hello world'
for i in range (20):
    uart_A.write (write_str)
    read_data = uart_B.read ()
    read_str = read_data.decode ('utf-8')
    print ("string =", read_str)
    if read_str == write_str:
        print ("baudrate: 115200 bits: 8 parity: None stop: 1 --- check Successfully")
uart_A.deinit ()
uart_B.deinit ()
del uart_A
del uart_B

3.2. Routine 2

AT module serial port

fm.register (board_info.WIFI_RX, fm.fpioa.UART2_TX)
fm.register (board_info.WIFI_TX, fm.fpioa.UART2_RX)
uart = machine.UART (machine.UART.UART2, 115200, timeout = 1000, read_buf_len = 4096)

3.3. Routine 3

Modify the baud rate of the REPL serial port

from machine import UART
repl = UART.repl_uart ()
repl.init (1500000, 8, None, 1, read_buf_len = 2048)

3.4. Routine 3

Modify the REPL serial port

from machine import UART

fm.register (board_info.PIN15, fm.fpioa.UART1_TX)
fm.register (board_info.PIN17, fm.fpioa.UART1_RX)
uart = machine.UART (UART.UART1, 115200)
UART.set_repl_uart (uart)