[General] RS485 reader using rpi pico

[roshV]

Hi,

I designed this schematic to read RS485 device. It works for 10-20 seconds and then hangs.
I have tried it also with a simple LED blinking programming, not reading RS485, and it still hangs.
The T&H sensor is not populated at the moment.

Any suggestions what am I doing wrong?

thank you

 

[Aussie Susan]

If it is working at all then the answer is most probably your software which you have not shown us or described in any way.
Susan

 

[roshV]

Hi, I tried very basic samples of LED blinking and also UART sending from RPI PICO W. For example this one:

from machine import Pin, Timer

led_onboard = Pin("LED", Pin.OUT)

def blink(timer):
    led_onboard.toggle()

Timer().init(freq=2.5, mode=Timer.PERIODIC, callback=blink)

It hangs with 10-20 seconds or around 3-6 timer calls. When I run the same program on the same RPI PICO W after taking it out of the PCB socket. The codes run for days.

 

[KlausST]

Hi,

basically your post#3 proves that it´s not a RS485 problem / UART problem

****
I´m with Susan. As long as you hide your code ... probably nobody can help you.

Klaus

 

[roshV]

Hi Klaus and Susan,

Many thanks for your help. Still working on the full code. Here it is so far.

The DHT sensor and also the interrupt switches are not attached. the pads are not populated at the moment.
The same code when the rpi pico is out of the PCB socket, works super well. I see the prints in Thonny REPL and also correct LED blinks for days.

As soon as put the RPI Pico in the socket of the above PCB. The LEDs blink for 10-20 seconds and then hangs. I also tried to clean RPI Pico with nuke flash and only had continuous onboard LED blinking code. Even that stops in 10-20 seconds, therefore, I was guessing it can be HW issue.

import gc
from machine import Pin, ADC, unique_id, UART, reset_cause, RTC, Timer, reset, lightsleep, idle
from utime import sleep, sleep_ms
from dht import DHT22
class UARTmain:
    def __init__(self):
        gc.enable()
        gc.collect()
               
        self.ledpin1 = Pin("LED", Pin.OUT) # Initialize onboard LED
        self.ledpin1.value(0)
       
        self.red = Pin(12, Pin.OUT) # Initialize onboard LED  red
        self.red.value(0)
       
        self.green = Pin(11, Pin.OUT) # Initialize onboard LED green
        self.green.value(0)
       
        # INITIALIZE READ/WRITE PINS & SETTINGS
        # =======================================================
        self.sensor = DHT22(Pin(19, Pin.IN, Pin.PULL_UP)) # Address the DHT22 Module
        #Interrupt pin configs
        self.interrupt_flag=0
        self.debounce_time=0
        self.pin = Pin(5, Pin.IN, Pin.PULL_UP)

        #opening the UART for reading TwinDos
        self.uart = UART(0, baudrate=38400, tx=Pin(16), rx=Pin(17))
        #self.uart.init(bits=8, parity=None, stop=2)
        self.tx_en_pin = Pin(18, Pin.OUT)
        self.tx_en_pin.value(0) #enable reception mode
       
        #------------------------------------
    def red_blink(self, times, dt):
        for x in range(times):
            self.red.value(1)
            sleep_ms(dt)
            self.red.value(0)
            sleep_ms(dt)
           
    def green_blink(self, times, dt):
        for x in range(times):
            self.green.value(1)
            sleep_ms(dt)
            self.green.value(0)
            sleep_ms(dt)
           
    def toggle_board_led(self):
        sleep_ms(100)
        self.ledpin1.value(not self.ledpin1.value()) # toggling
        sleep_ms(200)
        self.ledpin1.value(not self.ledpin1.value()) # toggling
   
   
    def get_uart_data(self):
        data = "nan"
        txData = b'get'
        rxData = bytes()
       
        for i in range(5):
            try:
                self.tx_en_pin.value(1) #enable transmission mode
                self.uart.write(txData) #sending uart data
                sleep(0.2)
                print("\n*Reading UART")
                self.tx_en_pin.value(0) #enable reception mode
                while self.uart.any() > 0:
                    rxData += self.uart.read(10)
                data=(rxData.decode('utf-8'))
                #print("twindos_data: ", twindos_data)
                result = data[:-1].split("#")
                instantaneous_power_used =int(result[1])
                total_power_used =int(result[2])
                return instantaneous_power_used, total_power_used
            except Exception as e:
                print("\n*Error reading uart, ",  e, "\nRetrying: ", i)
                sleep(1)
                continue
        return "nan", "nan"
   
    def read_and_blink(self):
        instantaneous_power_used, total_power_used = self.get_uart_data()
        print("\n*Power used: ", instantaneous_power_used, "\nTotal power used: ", total_power_used)
        self.green_blink(self, 2, 300)
        self.toggle_board_led()
       
        if instantaneous_power_used >  1000:
            self.red_blink(self, 4, 100)
            #self.red_blink(self, 4, instantaneous_power_used*0.1)
        else:
            self.green_blink(self, 6, 100)
            #self.green_blink(self, 4, instantaneous_power_used)
       
       
data_read_timer = Timer()
uart_data = UARTmain()
data_read_timer.init(period=(2000), mode=Timer.PERIODIC, callback=lambda t: uart_data.read_and_blink())