| 摘要 |
PURPOSE:To realize a refresh control by the 1-shot clock by providing a counter to count the refresh execution time and at the same time controlling correlation between the system clock and the refresh time point. CONSTITUTION:The RF execution time counter 5 is provided at the RF control part 2 to measure in the clock number the time required for the refresh RF execution of the memories 4-A-4-N, and the count control is carried out by the system clock SC1. At the same time, three RF time points are set in the RF period. The time of RF is set between the time points A and B; the sum of the maximum access time and the RF time between the time points B and C; and the RF time is set between the time point C and the final point respectively. Furthermore, the RF control is carried out at the active point of the normal SC1 and at the time point B, and then the RF is executed at the time point A after the RF period when the SC1 is stopped during the normal RF operation. And the RF is executed at the time point C of the RF period when the SC1 is stopped before operation of RF, and the RF is executed at the point A after the next RF period. |
