Adding a timer and the graphical LCD
This is a fairly big jump. With the LEDs and buttons tested, it is time to add the main graphical display, made from a Nokia cellphone display. Also, there is the main system timer event.
The simple user IO is working, and it is time to add a system timer. This will generate an interrupt every millisecond. In the final mouse a lot of work will be done in here – processing buttons, driving the LEDs, reading sensors and calculating drive signals for the motors.While that may seem a lot in a millisecond, the dsPIC used in primus can execute about 16,000 instructions in that tme and we should only need a small proportion of that time. (more…)