| 摘要 |
<p>PURPOSE:To obtain precise time synchronizing function by measuring time from the time of starting reception to the time when a CPU executes time synchronizing processing by a timer. CONSTITUTION:In a slave station, the timer 16 is started at the point of time of the start of the reception of reference time information, and the timer 16 is stopped at the point of time when a CPU 13 recognizes the completion of the reception. Further, the time of the sum of the reference time, a timer value and a fixed value for correction is set as the present time of its own station. For instance, when a transmission controller 11 receives transmission data, it starts a DMA controller 12 transfers gradually the receive data of the transmission controller 11 to a memory 14 as executing bus arbitration with the CPU 13. At that time, a gate 17 sends a start command to the timer 16 on the first data transfer by the DMA controller 12, that is, the AND condition of a hold permission signal from the CPU 13 and a write signal on a CPU bus. Thus, the time synchronization of god precision can be realized.</p> |
