I2C and UART don't work at the same time

Using Arduino Networking, Protocols, and Devices
1

I have a vesc motor controller that I am trying to talk to through UART on the RX and TX pins and an OLED 128x64 display I am trying to talk to through I2C. When I try a script only talking to the screen, it works fine. If I run a script only talking to the vesc, it runs fine. But running the following code results in the screen not being about to be initialized.

#include <VescUart.h>
//Screen
#include <Wire.h>
#include <Adafruit_SSD1306.h>

VescUart UART;
Adafruit_SSD1306 display(128, 64);

void setup() {
  Serial.begin(115200);
  while (!Serial) {;}
  UART.setSerialPort(&Serial);
  
  if (!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) {
    Serial.println("SSD1306 allocation failed");     //code get stuck here when run
    for(;;);
  }
  
  display.clearDisplay();
  display.setTextSize(1);
  display.setTextColor(SSD1306_WHITE);
  display.setCursor(0, 0);
  display.print("Loading...");
  delay(1000);
  
}

void loop() {
  if ( UART.getVescValues() )  {
    Serial.println(UART.data.rpm);
    Serial.println(UART.data.inpVoltage);
    Serial.println(UART.data.ampHours);
    Serial.println(UART.data.tachometerAbs);
    
  } else {
    Serial.println("Failed to get data");
  }
  display.display();
  delay(50);
  display.clearDisplay();
}
2

Please post a link to this, and a wiring diagram, with pins, connections and parts clearly labeled. Hand drawn is fine.

Please state which Arduino you are using.

3

Since the documentation is locked unless you have an account, you are kind of on your own. Look at your documentation/program code listing and see if they turn interrupts of and on.

1 Like
4

This is the motor controller.

image
image1920×2560 363 KB

5

This is a symptom of running out of dynamic memory. The screen takes half of it on a Classic Nano. The text-only SSD1306 library will solve that problem (no graphics).