I2C Screen LCD doesnt work on SparkFun LoRa Thing Plus expLoRaBLE

Development Boards Artemis
1

Hi Someone please help, I’m trying to use a 20x4 I2C LCD with my SparkFun LoRa Thing Plus expLoRaBLE. The screen works perfectly when I connect it to my Arduino Nano ESP32, but when I connect it to the LoRa Thing Plus the backlight turns on and no text appears on the screen.

BOARD MANAGER I USED (Apollo3) https://raw.githubusercontent.com/sparkfun/Arduino_Apollo3/master/package_sparkfun_apollo3_index.json and I select the (LoRa Thing Plus expLoRaBLE) I’m not sure if thats the board I should be selecting Someone please help.

What I tried:

Wiring
GND → GND
VCC → 5.V(VUSB)
SDA → 17
SCL → 16

”#include <Wire.h>
#include <LiquidCrystal_I2C.h>

LiquidCrystal_I2C lcd(0x27, 20, 4);

void setup() {
Wire.begin();
lcd.init();
lcd.backlight();

lcd.setCursor(0,0);
lcd.print(“Hello World”);
}

void loop() {
}”

Arduino IDE
Board selected: SparkFun LoRa Thing Plus expLoRaBLE
Using Wire.begin()

Other things I tested

  • Tried I2C address 0x27

  • Tried I2C address 0x3F

  • The same code works on the ESP32 but not on the LoRa board

Question:
Are pins 16 and 17 the correct I2C pins for this board, or does the Apollo3 require a different setup or library to use an I2C LCD?

Any help would be appreciated or anything had this issue and found the solution. Thanks!

2

Looks you need to change the connections. Connect SDA to pin 16, SCL pin 17

3

That board is a bit funky, its default i2c is assigned to the qwiic connector and D14 SDA, D15 SCL

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Those pins are only broken-out at the qwiic connector…and the qwiic connector outputs 3.3v, so trying to use a qwiic → 4 wires → LCD won’t work if the LCD needs 5v :-/

So my suggestion is to try using the above suggestion (re-wire SDA to 16 & SCL to 17) but you’ll probably need to use a software i2c, something like GitHub - Testato/SoftwareWire: Creates a software I2C/TWI bus on every pins · GitHub

4

I had another look about my advice and TS-Russell is correct that Qwiic is the primary Wire. On pin16 and 17 is Wire1 allocated. I have looked at a number of libraries that contain LiquidCrystal_I2C.h on github but none of them does allow selecting Wire1 from the sketch. As alternative to TS-Russell advice, can you share (a link - name- to) the library you use. I can try to adjust it to select Wire1.

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