| 摘要 |
PURPOSE:To prevent write error by outputting a write command signal to a memory in the non-output state of a dissidence signal from an address signal comparison means and providing a write control means stopping the output of the write command signal based on the dissidence signal. CONSTITUTION:If solder is stuck to the 2nd address bus 9 and the bus 9 is short-circuited, it is possible that an address signal of the 1st address bus 2 and an address signal of the bus 9 are might be dissident. In this case, the address signal of the bus 2 and the address signal of the bus 9 are compared by an address signal comparison means 5 and if both the address signals are dissident, a dissidence signal DAD is outputted via an OR gate 6 and an FF7 from the means 5. A write control means 4 stops the output of the write command signal WR2 to a memory 8 based on the signal DAD. Thus, no write is given to the memory 8 and the original data is kept as it is. |
