| 摘要 |
PURPOSE:To obtain various clocks easily and to realize economical and miniature constitution, by dividing a clock by using a microcomputer. CONSTITUTION:In one-chip microcomputer muCPU, a clock needed for its operation is generated, by applying the oscillation output from crystal oscillator XTL to clock generator CG, and then supplied to each part of muCPU. Corresponding to the count contents of program counter PC, programs for clock dividing and other processes are read out from memory ROM. Next, a machine cycle number among respective instruction cycles of muCPU is constant and each instruction execution time becomes constant. Therefore, access to an output port is attained at a period of the constant instruction step number to execute output instructions, so that a constant-period clock can be outputted from the output port. |
