Komunikasi antara dua mikropengawal melalui UART

Hari ini kita akan memperkenalkan protokol UART.

komponen yang digunakan

• Seeduino Xiao RP2040 (Penghantar)
• Maker Nano RP2040 (Penerima)
• Grove CO2 Sensor
• Grive OLED Display SSD1315
• Grove Shield for Arduino Nano V 1.1
• Grove Shield for Seeeduino Xiao

Secara ringkasnya, bacaan CO2, Suhu dan Kelembapan dibaca oleh Penghantar, kemudian nilai pembolehubah dihantar kepada penerima, dan dipaparkan di atas OLED.

saya merujuk kepada artikel ini

#ini adalah Penghantar UART dipasang di atas Seeeduino Xiao RP2040
import time
import board
import busio
import digitalio
import adafruit_ssd1306
import adafruit_scd30

#Seeduino Xiao RP2040 mempunyai definisi port I2C sedia terbina
i2c = board.I2C()

#Seeduino Xiao RP2040 mempunyai definisi port TX, RX sedia terbina
uart = busio.UART(board.TX, board.RX, baudrate=9600, timeout=0)

UPDATE_INTERVAL = 5
last_time_sent = 0
while True:
    try:
        #oled.fill(0)
        now = time.monotonic()
        if now - last_time_sent >= UPDATE_INTERVAL:
            scd = adafruit_scd30.SCD30(i2c)
            temperature = "{:.2f}".format(scd.temperature)
            relative_humidity = "{:.2f}".format(scd.relative_humidity)
            co2_ppm_level = "{:.2f}".format(scd.CO2)
            print("CO2: "+co2_ppm_level+" ,Temperature : "+temperature+" Humidity "+relative_humidity)
            
            #send UART message
            uart.write(bytes("<R,"+co2_ppm_level+","+temperature+","+relative_humidity+">", "ascii"))
            last_time_sent = now

    except:
        print("something wrong somewhere")
Code language: PHP (php)

#ini adalah penerima UART dipasang di atas Maker Nano RP2040
import time
import board
import busio
import digitalio
import analogio
import adafruit_ssd1306

#Maker Nano RP2040 tiada definisi port I2C sedia ada dalam board
LCD_SDA = board.GP12 
LCD_SCL = board.GP13
i2c = busio.I2C(scl=LCD_SCL, sda=LCD_SDA)
oled = adafruit_ssd1306.SSD1306_I2C(128, 64, i2c)

# Use a timeout of zero so we don't delay while waiting for a message.
uart = busio.UART(board.GP4, board.GP5, baudrate=9600, timeout=0)

message_started = False

while True:
    byte_read = uart.read(1)  # baca 1 byte melalu UART
    if byte_read is None:
        # Nothing read.
        continue

    if byte_read == b"<":
        # mula kumpulkan mesej tanpa "<".
        message = []
        message_started = True
        continue

    if message_started:
        if byte_read == b">":            
            # Akhir mesej, tanpa ">".
            # Tukar kepada string dan pecahkan ikut tanda ","
            message_parts = "".join(message).split(",")
            message_type = message_parts[0]
            message_started = False            
            if message_parts[0] == "R":
                # Received a message telling us a all sensor values
                co2=message_parts[1]
                temperature=message_parts[2]
                humidity=message_parts[3]
                print(f"CO2 {co2}")
                print(f"T {temperature}")
                print(f"H {humidity}")
                #Display on OLED
                oled.fill(0)
                oled.text("https://sidik.my",20,0,1)
                oled.rect(2, 10, oled.width-2, oled.height-10, True)
                oled.text("CO2:" , 4, 15,1)
                oled.text(co2, 20, 15, True, size=3)
                oled.text("T:"+temperature, 20, 45, True, size=1)
                oled.text("H:"+humidity, 70, 45, True, size=1)
                oled.show()
            
        else:
            # Accumulate message byte.
            message.append(chr(byte_read[0]))
Code language: PHP (php)