Arduino Serial communication with CH340G chip

Issues and Errors
1

Has anyone had any experience with the cheap arduino knock-offs that use the CH340G family of serial chips? I just got one of these boards (an Uno clone), installed the driver, and all works great… until I add in the Blynk library. Here’s the relevant code. This is for a simple ‘blink’ sketch.

void setup() {
    Blynk.begin(auth);
    Serial.begin(115200, SERIAL_8N1);
    Serial.println("Starting up...");
    pinMode(ledPin, OUTPUT);
}

With the Blynk.begin() command, serial communication is garbled, even if Blynk itself is doing nothing else (i.e. no Blynk.run() anywhere). If I disable Blynk.begin() then I can communicate via serial just fine.

Has anyone else run into this? I’ve tried all manner of serial comms parameters, baud rates etc, nothing makes any difference except whether Blynk.begin() is called. Identical sketch run on my Yun works just fine with or without Blynk.

The other interesting thing is that with Blynk enabled on the clone, the LED (pin 13) doesn’t actually blink… it’ll either be solid on, or solid off, but doesn’t change until the sketch is re-uploaded.

2

i have some Arduino Uno and Arduino nano with the same chip from china under 3 dollars and working fine with Blynk.

i think you should close your serial monitor (as UNO has only one hardware serial) and run the script in the library to communicate with Blynk server .

or use soft serials if you want to continue read the serial debugging .

3

Can you expand on "run the script in the library to communicate with Blynk server " ?

Also, any idea why pin 13 would be affected by Blynk with this sort of board?

4

the script is already in the library

for windows user blynk-library/scripts/blynk-ser.bat
for make users blynk-library/scripts/blynk-ser.sh

and PIN13 is connected to an LED on most of Arduino board use for Debugging and testing , that is why most of the samples will try to manipulate its status.

5

Thanks for your responses. I guess I should have been clearer - any idea why a simple blink sketch would fail (pin 13 doesn’t blink) when using Blynk with a CH340G-based board? This issue of course may have nothing to do with the serial chip - all I know is when I disable Blynk, the sketch works perfectly.

6

As far as the blynk-provided serial scripts, there’s no sane reason why they should work where a python script fails - especially when said python script is working perfectly if I disable Blynk.

So the issues seem related to running Blynk on this device, rather than the particular serial communication program I’m using. I’m wondering therefore if Blynk.begin() sets up serial params of its own that either the chip can’t handle, or that simply conflict with the chip’s operation in some way.

Time to dig into the code…

7

I have a clone Uno with the CH340G serial, and I’ve got it working with with blynk sending and recieving data just fine. I think the issue is with communication; forgive me if I’m wrong, but if your device doesn’t have WiFi/Ethernet capabilities I think to communicate with the Blynk servers, Blynk.begin hijacks the serial port on your arduino to send and recieve data from the script running on your PC, through the USB COM port. This would explain why your Yun is working, as it has other communication methods, so doesn’t need to send Blynk data through the COM port

1 Like
8

Ah! That make sense - thanks! The device indeed does not have any networking capabilities, so I bet that’s what’s going on.