CODEWITHSUNDEEP
c++raspberry-pii2c
user2762996
user2762996

Reputation: 626

Getting notified when an I2C-Value changes in C++

I recently started experimenting with I2C-Hardware on my raspberry pi. Following this tutorial Using the I2C interface I already know how to read and set values. However, the program I want to realize needs the current value on a specific address all the time. So, I made a thread and query the value constantly in a never ending loop, which seems primitive to me. Is it possible to get notified in an event-like manner when a value on an I2C-adress changes? A platform independend solution would also be much welcomed.

Upvotes: 2

Views: 374

Answers (2)

PMF
PMF

Reputation: 17298

Generally speaking, the I2C bus has no interrupt capability. So with only I2C, all you can do is poll the chip for a certain event to happen or value to change.

Most chips do have an interrupt line (sometimes even more than one) that can be programmed to trigger on certain events. The behavior of this line depends on the chip. Usually it needs to be enabled (using I2C commands) and it needs to be linked to a GPIO input line. For these, interrupt support is available.

Upvotes: 2

user2762996
user2762996

Reputation: 626

I was able to get what I wanted.

I use the following repeater for the I2C-Bus: link and it turns out there is a soldering bridge (LB2) you can set that sets a signal on GPIO17 whenever a value on the I2C-Bus changes since it has last been changed. I can now listen on this events accordingly.

Upvotes: 2

Related Questions