5. Serial Communication Experiment

Routine Code

from fpioa_manager import fm
from machine import UART
import time

# binding UART2 IO:7->RX, 8->TX
fm.register(7, fm.fpioa.UART2_RX)
fm.register(8, fm.fpioa.UART2_TX)

yz_uart = UART(UART.UART2, 115200, 8, 0, 0, timeout=1000, read_buf_len=4096)

write_bytes = b'hello'
last_time = time.ticks_ms()

try:
    while True:
        # send data per 500ms
        if time.ticks_ms() - last_time > 500:
            last_time = time.ticks_ms()
            yz_uart.write(write_bytes)
        # read and print data
        if yz_uart.any():
            read_data = yz_uart.read()
            if read_data:
                print("read_data = ", read_data)
except:
    pass

yz_uart.deinit()
del yz_uart

Experiment Preparation

1. Prepare a USB-to-serial adapter and 4-pin jumper wires.
1. Connect the K210 to the serial adapter with 4-pin jumper wires as shown below:

1. Connect the serial adapter and K210 to your computer via USB.
1. Open UartAssist. In the serial settings at the top-left, configure the parameters and select the serial adapter's port (check Device Manager for the port number), then click Open. After UartAssist connects to the serial adapter:

1. Open CanMV IDE, connect to the K210, and run the routine code above.
1. Check the data log in UartAssist.

Experiment Results

1. After running, the K210 performs simple bidirectional UART2 communication: it sends the byte string b'hello' every 500 ms and continuously checks the receive buffer, reading and printing any received data. The UartAssist data log displays messages sent by the K210.

1. The IDE Serial Terminal prints data received by the K210 from the serial adapter.

Routine Code Explanation

1. Import the modules required to run the routine. fm from fpioa_manager configures chip pin functions. UART from machine implements serial communication.

from fpioa_manager import fm
from machine import UART
import time

1. Use fm.register to configure pin 7 as UART2 RX and pin 8 as UART2 TX.

fm.register(7, fm.fpioa.UART2_RX)
fm.register(8, fm.fpioa.UART2_TX)

1. Create a UART object named yz_uart.
  UART.UART2: use UART2.
  115200: baud rate 115200.
  8: 8 data bits.
  0: no parity bit.
  timeout=1000: read timeout 1000 ms.
  read_buf_len=4096: receive buffer length 4096 bytes.

yz_uart = UART(UART.UART2, 115200, 8, 0, 0, timeout=1000, read_buf_len=4096)

1. Define the byte data to send as b'hello' and record the initial timestamp in last_time.

write_bytes = b'hello'
last_time = time.ticks_ms()

1. Enter an infinite loop and ignore any exceptions during execution.

try:
    while True:

except:
    pass

1. Send data every 500 ms. When the interval exceeds 500 ms, update the timestamp and send write_bytes via UART.

if time.ticks_ms() - last_time > 500:
    last_time = time.ticks_ms()  
    yz_uart.write(write_bytes)

1. Read and print received data. Check if the UART receive buffer has data; if so, read and print it.

if yz_uart.any():  
    read_data = yz_uart.read()  
    if read_data:  # If valid data was read
        print("read_data = ", read_data)

1. Call yz_uart.deinit() to deinitialize the UART and release resources, then del yz_uart to clean up memory.

yz_uart.deinit()
del yz_uart