Search dir only for header files requested with #include "file" they are not searched for #include, before all directories specified by -I and before the standard system directories. If dir begins with =, then the = will be replaced by the sysroot prefix see -sysroot and -isysroot. If the directory dir is a standard system include directory, the option is ignored to ensure that the default search order for system directories and the special treatment of system headers are not defeated. Directories named by -I are searched before the standard system include directories. searches the "system" paths, while "." searches both the system an "local" paths.Īdd the directory dir to the list of directories to be searched for header files. That's because they are computed in the same way, and onReceive, which is called from an interrupt handler, is non-interruptible, as any other Arduino interrupt handler.The proper distinction is exactly what paths are searched for the include files. From the Wire library source code I also learned that the integer argument passed to onReceive is the same thing returned by Wire.available() before any reads are done. I'm not sure what exactly confuses Arduino so that it receives more data than Raspberry Pi sends, but it's good to clear the buffer as a safety measure in case someone writes more data by accident. So the solution looked simple to me on onReceive, just read from the buffer until it's empty, to make sure it's called the next time data arrives. Apparently Wire library is not accepting any more data unless the buffer received from the previous i2c operation is completely read from! Since it's hard to debug an onReceive/onRequest handler via a Serial console (merely because doing Serial operations in an interrupt handler is impossible), I had to look through the Arduino libraries code trying to guess what's going on.Īfter a while I found a set of instructions that looked suspicious. It was bothering me for a while until I decided to figure it out yesterday. In practice it is seen as if an Arduino gets stuck sending -1 to whatever request it receives. All Arduinoes are operating in slave mode, the bus master is a Raspberry Pi board.įor this apparently you have to install both onReceive and onRequest handlers the "write" operation is simply handled by onReceive by receiving the register and immediately after that a new value the "read" is a bit more complicated, as onReceive receives the register from the wire, and then onRequest that follows needs to send the data.Īll that works quite fine until the speed at which Raspberry Pi queries the Arduinoes is skyrocketing to where Wire library apparently gets confused. So I was implementing an i2c slave on the Rover's Arduinoes the one that could be read from and written to.
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