Solving the Puzzle of Arduino Wire Library Stop

When working with the Arduino Wire library, you may encounter situations where it seems like the library is not functioning as expected. In this article, we will explore one such issue and provide a solution to overcome it.

The problem arises when trying to communicate with an old microprocessor via I2C (2Wire) using the Arduino board's soft I2C implementation. Specifically, the issue is that the library keeps sending a 'Stop' signal when the repeated start mode is invoked, which can lead to errors and unexpected behavior.

To understand this better, let's take a closer look at the data logs captured during the communication process. In our case, we noticed that the data line should not go low at certain points, and the last clock signal should not be sent when 'repeated start' is invoked.

After analyzing the code, it became clear that the issue lies in the `Wire.endTransmission(false)` function call. By default, this function sends a 'Stop' signal when set to true, which is not what we want in this case. We need to modify the library to register an 'Sr' instead of the 'P' and 'S' signals.

Fortunately, Arduino Wire library has been updated to include a Boolean parameter that allows us to keep the line open. By passing `false` to `Wire.endTransmission`, we can prevent the transmission from ending with a 'Stop' signal.

In our case, this meant changing the code to use `Wire.endTransmission(false)` instead of `Wire.endTransmission(true)`. This simple modification allowed us to successfully communicate with the old microprocessor via I2C without any issues.

If you are experiencing similar problems when working with the Arduino Wire library and soft I2C implementation, we hope this article has provided some insight into the solution. Remember to carefully analyze your data logs and code to identify potential issues, and don't hesitate to experiment with different solutions until you find one that works for you.

Arduino wire library stop