twi.writeTo problem not declared

Projects Programming
1

I am playing with a multiplexer that will connect to 3 BNO055's. I am working on the basic multiplexer detection and i get a "not declared in this scope" errror on twi.writeTo what should it be declared as ??

#include <Wire.h>
#include <Adafruit_BNO055.h>


#define BNO055_SAMPLERATE_DELAY_MS (20)     // Set pause between samples

#define TCAADDR 0x70

void tcaselect(uint8_t i) {
  if (i > 7) return;
 
  Wire.beginTransmission(TCAADDR);
  Wire.write(1 << i);
  Wire.endTransmission();  
}

Adafruit_BNO055 bno0 = Adafruit_BNO055();     // Use object bno to hold information

void setup() {
  Serial.begin(9600);                          // open the serial port at 9600 bps: 

    while (!Serial);
    delay(1000);
 
    Wire.begin();
    
    Serial.begin(115200);
    Serial.println("\nTCAScanner ready!");
    
    for (uint8_t t=0; t<8; t++) {
      tcaselect(t);
      Serial.print("TCA Port #"); Serial.println(t);
 
      for (uint8_t addr = 0; addr<=127; addr++) {
        if (addr == TCAADDR) continue;
      
        uint8_t data;
        if (! twi_writeTo(addr, &data, 0, 1, 1)) {
           Serial.print("Found I2C 0x");  Serial.println(addr,HEX);
        }
      }
    }
    Serial.println("\ndone");

}
2

Here is the compiler error

TEST_TEST_TEST:40: error: 'twi_writeTo' was not declared in this scope

if (! twi_writeTo(addr, &data, 0, 1, 1)) {

^

exit status 1
'twi_writeTo' was not declared in this scope

3

Your project is called "TEST_TEST_TEST" ? with the sketch being "TEST_TEST_TEST.ino" ?
The compiler has a problem at line 40 with the function "twi_writeTo". The compiler says that you want to call it, but that function is not declared somewhere, it does not exist.

Have you gathered little pieces of code from the internet ? The "twi_writeTo" is not a normal Arduino function.
Are you trying to run a I2C Scanner ? Try this one: Arduino Playground - I2cScanner.

Please tell us also which Arduino board that you are using, and which multiplexer and how it is connected.

4

The twi code came from the mutiplexer look up

Adruino UNO

Switch IC Development Tools TCA9548A I2C Multiplexer

nothing is hooked up yet i am working on the code before i build it. I will hook up the multiplexer to the SDC SDA pins.

The code example I used was

I forgot to use #include "utility/twi.h"

it now got past the first error but now is throwing this error below. I feel like i am missing something simple any help is appreciated. Thanks

undefined reference to `twi_writeTo(unsigned char, unsigned char*, unsigned char, unsigned char, unsigned char)'

5

I got it i'm an idiot, i was not including the correct library.

6

No, no, you are not, but at Adafruit they are. I am very unhappy that Adafruit is using a low level function of the Arduino Wire libary :smiling_imp: They should have used the normal functions of the Wire library. The more I think about it, the more I am convinced that they should not have done that.

This is the low level twi_writeTo : https://github.com/arduino/Arduino/blob/master/hardware/arduino/avr/libraries/Wire/src/utility/twi.c#L226.
These are the normal functions of the Wire library: Wire - Arduino Reference