[George]

Hi Renzo

I had a similar problem and I think I found the source of the bug.
The bug occurs when using a String type variable for the message. The Sender does not send the last character of the String.
Ex: When sending “101”, the Sender sends “10”, that is, it does not send the last character.
Ex:

static int msg = 100;
msg++;
String msg_sent = String(msg);
Serial.print("Sent Message: ");
Serial.println(msg_sent);
ResponseStatus rs = e220ttl.sendMessage(sent_msg);

I think the bug is on line 831:
https://github.com/xreef/EByte_LoRa_E220_Series_Library/blob/7acecaede468559df9a2e8ccf7367059748df80c/LoRa_E220.cpp#L831

At the moment:
byte size = message.length(); // sizeof(message.c_str())+1;

I changed it to:
byte size = message.length() + 1; // sizeof(message.c_str())+1;

Everything worked fine.

There are other parts of the code that may need fixing. (I haven’t tested yet)
Ex:
https://github.com/xreef/EByte_LoRa_E220_Series_Library/blob/7acecaede468559df9a2e8ccf7367059748df80c/LoRa_E220.cpp#L850

[George]

Hi Renzo

I’m traveling now. Next Sunday (01/05), I will perform more tests and send the results.

Thank you very much for your attention and for the development of the library.

[George]

Thank you very much, Renzo

I bought EBYTE 220 modules. I started testing with their fantastic library.

If I identify something “strange”, I will open a post here on the forum.

I’m not a professional programmer (I know R Language and I’m a beginner in C/C++). But I will try to test and send feedback.

I sent an email to EBYTE with the suggestion that they finance/sponsor the development of their library.

Thank you very much.

[George]

If you do not activate “#define ENABLE_RSSI true” the modules do not communicate correctly. There is a lot of data loss in sending and receiving.
When I activate “#define ENABLE_RSSI true”, the modules communicate correctly, but there are the bugs reported in the posts above.

[George]

Update:
The above mentioned strategy of using String msg_txt = String(msg_num) + String(" "); did not fix the RSSI bug. It just froze the RSSI number at a certain value.
See attached image:

Attachments:

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[George]

NOTE: When compiling the code in VSCode + Platformio, this warning appears:

Building in release mode
Compiling .pio\build\nodemcuv2\src\main.cpp.o
Compiling .pio\build\nodemcuv2\lib14b\EByte_LoRa_E220\LoRa_E220.cpp.o
.pio\libdeps\nodemcuv2\EByte_LoRa_E220\LoRa_E220.cpp: In member function 'void LoRa_E220::writeProgramCommand(PROGRAM_COMMAND, REGISTER_ADDRESS, PACKET_LENGHT)':
.pio\libdeps\nodemcuv2\EByte_LoRa_E220\LoRa_E220.cpp:552:12: warning: unused variable 'size' [-Wunused-variable]
  552 |    uint8_t size = this->serialDef.stream->write(CMD, 3);
      |            ^~~~
Archiving .pio\build\nodemcuv2\lib14b\libEByte_LoRa_E220.a
Linking .pio\build\nodemcuv2\firmware.elf
Retrieving maximum program size .pio\build\nodemcuv2\firmware.elf

[George]

Update: The bug is not worked around with the suggestion below. See the next posts.
I got around the “bug” by concatenating a space at the end of the message. There is no data loss and the receiver receives the complete numbers.

String msg_txt = String(msg_num) + String(" ");
ResponseStatus rs = e220ttl.sendMessage(msg_txt);

[George]

Hi Renzo

Thank you very much for your dedication and willingness to provide libraries for EBYTE’s E32, E22, and E220 modules.

About your observation:
“I think the E220 is a candidate for the best device, but 400b of the buffer can be dangerous if you want to use the max packet size and receive three messages simultaneously, you can lose one of them.”

I was wondering how critical this would be in a production environment.

First, do Semtech modules have a storage buffer (or is it just an EBYTE increment)?
In the case of the E220, considering that each “Message size bytes” is 200 bytes, and the “Buffer size bytes” is 400, I wanted to know how this can be something critical in the production environment.

Fictitious Example:
If in a period of 5 seconds, a gateway/ESP32/E200 receives 3 messages of 200 bytes, can one of them be lost?
How long does an E220 take to process a 200-byte message and transmit it to the microcontroller (eg: E220 -> ESP32)?

Sorry to bother you, but I’m trying to understand from an operational perspective how critical this is.

Thank you for your attention.

[George]

I just identified that it is possible to choose the frequency using #define.

I saw this on github: https://github.com/xreef/EByte_LoRa_E22_Series_Library

# define  FREQUENCY_433 
# define  FREQUENCY_170 
# define  FREQUENCY_470 
# define  FREQUENCY_868 
# define  FREQUENCY_915

Thank you Renzo

[Author]

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