View Full Version : Can I use standard I2C to an external device with the audio board active?

06-10-2016, 02:07 AM
Believe it or not I am running out of GPIO pins even with the Tindie breakout board. To save pins I would like to use I2C to talk to external devices, but I note that the Audio board has the SDA and SCL pins active for its own use. The question is can I use the standard I2C bus at the same time, without enabling the alternate pins? I guess another way to ask is: how busy is the standard bus while the Audio board is active? I seem to remember reading somewhere that it is only used for passing parameters... My use would be only sporadic - maybe 20 bytes/second at most.

06-10-2016, 06:13 AM
Yes, you can use I2C, as long as your I2C chips use different I2C addresses.

The audio lib only uses I2C for configuration at startup, and when you call functions to change SGTL5000 settings.

06-10-2016, 06:20 AM
The audio board uses SDA/SCL as a standard i2c bus to talk to the SGTL5000 (address 0x0A) and the WM8731 (address 0x1A). It provides pull-up resistors already, so you don't have to add additional resistors.

Note, the Audio library uses the standard Wire.h library and not the t3_i2c.h library. This means you need to use Wire.h in your programs.

I don't know how frequently the audio library uses the i2c bus.