| 摘要 |
PURPOSE:To perform an RAM refresh when a power supply is powered-on with a simple and miniature constitution, by refreshing the RAM via a memory control circuit after detecting the reading of a program ROM. CONSTITUTION:When an address is applied from a microprocessor 1 via a bus 2 with power-on of a power supply, a decoder 6 detects that a program ROM7 received a reading access. This detecting signal 15 is applied to the ROM7 as well as to a memory control circuit 9. An RAM8 is refreshed via the circuit 9 and synchronously with the program reading of the ROM7. Thus the refresh is possible without having any complicated procedure nor discontinuing the operation of the processor 1. This simplifies and miniaturizes the constitution of a circuit for refresh of the RAM when a power supply is powered-on. |
