| 摘要 |
PURPOSE:To prevent the disturbance of output data during switching, by switching the output data of the system that is changed from the holding system to the working system with a synchronization secured with the data output period. CONSTITUTION:A synchronization is secured for the duplication switch signal (d) by the FF13 at the rear edge of the strobe signal (f) serving as the data period discrimination signal. In case a switching is carried out during the holding state, the DTFF14 is cleared. And the enable signal (k) becomes immediately ''L'' to lock the output gates 9 and 10 to be cut off from the output bus signals (g) and (h). In the case of switching to the working system, the FF14 is set after setting of the FF13 with a delay of a data period. Then the signal (k) becomes ''H'' with a delay to be connected to the signals (g) and (h). In other words, a switching is given to the output data of the system that changes to the working system from the holding system with a synchronization secured with the data output period. As a result, the disturbance during switching can be prevented for the output data. |
