Thursday, December 10, 2009

PIC10 Instruction Cycle

A typical sequence of executing instructions of microcontroller is:
  • fetching the instruction from memory
  • decoding the fetched instruction
  • fetching the data from memory depending on instruction
  • executing the instruction.

In microchips PIC10 family the MCU clock is internally divided by four. These divided clocks are non-overlapping clocks i.e none of the clock stars at the same time, they execute sequentially.

The quadrature clock namely Q1, Q2, Q3 and Q4. An instruction cycle is of four clock cycle. The Q1 clock increments the Program Counter(PCL) to fetch the instruction to be executed. The instruction is executed within clock Q2, Q3, & Q4. The clock Q2 and Q4 are to read and write data in to memory respectively, depending on the instruction. The instruction is executed in clock Q3. Every instruction is executed in one quadrature clock because of pipeline.

No comments:

Post a Comment