instruction cycle clock cycle oscillator
Hi,
the clock cycle is the period of the clock that you're feeding the to the micro (for example, a clock cycle takes 1us if the oscillator's frequency is 1MHz). The instruction cycle depends on the internal structure of the microcontroller or processor you use. For instance, the for a PIC an instruction cycle takes 4 clock cycles, for an 8051 it takes 12 cycles, for the AVRs take 1 cycle. This is because an instruction has multiple stages, like fetch, decode, execute and writeback. For some of the micros, the instruction cycle takes fewer clock cycles because they have a mean to paralelly do multiple operations (pipelining) - like executing an instruction, decoding the next one and fetching the next one from the program memory. Some of microchip's datasheets explain these stages pretty well.