During the��last couple of weeks I have worked on implementing most of the sysex-based messages. This was great fun, because it greatly facilitates interaction between Pharo on any platform and the real world with a variety of devices. Now I am at the point where I have to address the fundamentally asynchronous��nature of the Firmata protocol. At present we store the answers from requests in instance variables, but we don't know when these are available. Sometimes the protocol allows for continuous��updates, so reading the data is semi-realtime. This happens with analog inputs, but can also be used with i2c devices or encoders. Driving a stepper motor really needs a callback or notification mechanism. When you instruct the stepper to do a number of steps you must be notified when it is ready for the next move.

At this point I want your input on what is the "Pharoic" way of doing this. I can think of announcements or using��Taskit, or simply passing a block to be executed when the answer becomes available. Maybe someone can point��me to examples in existing packages. By the way, in WiringPi this callback facility also is missing (wiringPiISRPin: pinNumber edgeType: edgeType function: aFunctionPointerOrCallback >>��shouldBeImplemented).

regards

rob van lopik