Hi, turns out the Curie device has hardware PWM counters in addition to the Timer1 counter as revealed in "variant.h" and related files and the schematic pin name PWM0/SS10_3V_IO3. Each pin has two source/destinations defined as Mode A and Mode B in "scss_registers.h" and related files. For the PWM pins 3, 5, 6 and 9, Mode B connects to a set of hardware PWM counters while Mode A connects to the GPIO. Mode A is the default setting. Intel decided for some reason to not use these counters in any of the PWM library examples. I developed a library exposing these counters: CurieHwPWM. This approach is an improvement over the ISR software driven approach. I welcome feedback on the library features or coding.
Lee