I2c working with arduino uno but not with mega

Projects Networking, Protocols, and Devices
1

Hello, I'm trying out my new TEA5767 FM radio and it doesnt want to work if i connect it to my arduino mega however it does work when i connect it to the uno.
pin layout:
GND -> GND
Vcc -> 5v
SDA -> SDA(pin 20)
SCL -> SCL(pin 21)

and for the uno i connect the i2c using pin a4 and a5

code i'm using:

#include <Wire.h>
#include <TEA5767Radio.h>
 
TEA5767Radio radio = TEA5767Radio();
 
void setup()
{
  Wire.begin();
  radio.setFrequency(102.4);
}
 
void loop()
{
}

Is there anything i'm doing wrong and what should i do to get it working on my mega.

2

Have you used the I2C on the Mega board before ?
Which libary did you use ( a link to that library please ).
Pin 20 and 21 is okay : Wire - Arduino Reference
Can you make a photo of it ?

3

Koepel:
Have you used the I2C on the Mega board before ?
Which libary did you use ( a link to that library please ).
Pin 20 and 21 is okay : Wire - Arduino Reference
Can you make a photo of it ?

Hello, i have used i2c before but it didnt work aswell, but for that specific problem i found a libary that support different io pins(and now that works) so on pin 21 and 20 i never got it working.
I will do a test to see if the pins even work...

here is the picture:

(there are lots of other things connected to it so dont mind the big mess XD)

EDIT: The pins do work i tested it with a LED and it works.
EDIT 2: The pins also seem to give out a signal high when there is no code on the arduino at all, they will always give a high signal it seems.

4

You could try the i2c_scanner : Arduino Playground - I2cScanner
It should detect the TEA5767. If it can find nothing, the Mega board might be broken.
What kind of Mega board is it ? A "TDuino" or "ZDuino" or a Geeetech "IDuino" ? That is not an official Arduino Mega 2560 board.

The Geeetech IDuino seems to have a defective board, the SCL is not connected, so the I2C bus won't work:
http://www.geeetech.com/forum/viewtopic.php?f=16&t=16053
http://www.geeetech.com/forum/viewtopic.php?f=16&t=16011

If you have a defective board, or if the ATmega2560 chip has been damaged, you need a new Mega board anyway.

5

Koepel:
You could try the i2c_scanner : Arduino Playground - HomePage
It should detect the TEA5767. If it can find nothing, the Mega board might be broken.
What kind of Mega board is it ? A "TDuino" or "ZDuino" or a Geeetech "IDuino" ? That is not an official Arduino Mega 2560 board.

The Geeetech IDuino seems to have a defective board, the SCL is not connected, so the I2C bus won't work:
http://www.geeetech.com/forum/viewtopic.php?f=16&t=16053
Iduino MEGA R3 SCL problem - Geeetech

If you have a defective board, or if the ATmega2560 chip has been damaged, you need a new Mega board anyway.

Thank you for your help, it is indeed a Iduino. atleast now i know that what ever i try will not work, what arduino clone would you recommend? to poor for the real ones XD

6

Try Ebay or AliExpress. Buy a 'R3' version.
If you are going to buy a cheap clone, you might as well buy the cheapest one of them all. The very cheap boards have a CH340G usb-serial chip, you need to install a driver for that.

A clone with a funny name (ZDuino, IDuino) or no name at all is legal. However, a clone with the 'Arduino' name is not legal, because it was not made by Arduino and does not have the good quality components of a real Arduino board.

At AliExpress.com, the cheapest Mega 2560 R3 is 6 dollars. It has the CH340G, and it doesn't illegally use the name "Arduino" : http://www.aliexpress.com/store/product/Mega-2560-R3-Mega2560-REV3-ATmega2560-16AU-CH340G-Board-ON-USB-Cable-compatible-for-arduino-No/1516062_32386948507.html

7

Koepel:
Try Ebay or AliExpress. Buy a 'R3' version.
If you are going to buy a cheap clone, you might as well buy the cheapest one of them all. The very cheap boards have a CH340G usb-serial chip, you need to install a driver for that.

A clone with a funny name (ZDuino, IDuino) or no name at all is legal. However, a clone with the 'Arduino' name is not legal, because it was not made by Arduino and does not have the good quality components of a real Arduino board.

At AliExpress.com, the cheapest Mega 2560 R3 is 6 dollars. It has the CH340G, and it doesn't illegally use the name "Arduino" : http://www.aliexpress.com/store/product/Mega-2560-R3-Mega2560-REV3-ATmega2560-16AU-CH340G-Board-ON-USB-Cable-compatible-for-arduino-No/1516062_32386948507.html

Thank you!
Anyways is there a way i could connect it to different pins for i2c and if so what would i need to use and how?

8

Perhaps you can spot the missing connection and solder it.
The SDA and SCL are also next to AREF, near the USB connector. Scroll down for the picture here : https://arduino-info.wikispaces.com/MegaQuickRef
Or this:

Another option is a software I2C on two digital pins, there is a SoftwareWire in the Library Manager.