| 摘要 |
<p>PURPOSE:To simplify software and to reduce the load of a CPU by using a circuit which decides the end of a data writing action on an EEPROM. CONSTITUTION:An unaccessible flag is set to an EEPROM state by a CPU 1 and also addresses and data are latched by an address latch 3 and a data latch 4 respectively. At the same time, the write signal is latched by a write signal latch 5. Then a timer of a writing end deciding circuit 6 is started. The data written on a EEPROM 2 are read out via both latches 3 and 5 when a fixed time set by a timer is passed. Then the contents of the latch 4 are compared with those of the circuit 6 by a coincidence circuit 6. When coincidence is attained between both contents, the circuit 6 decides the end of a writing action and the flag 7 is reset by the circuit 6. Thus the end of a data writing action on the EEPROM is decided by hardware with no use of the software. Then the software is simplified and the CPU load is reduced for a microcomputer device containing the EEPROM and the CPU formed in a single chip.</p> |
