| 摘要 |
PURPOSE: A method for preventing the damage of a program area of a memory is provided to protect a program area of a RAM by a memory protection unit in case of using a CPU device with low price. CONSTITUTION: A CPU(100) is widely used as a main control device in a general digital electronic circuit system, and to control a general RAM(200) and a memory protection unit(300). When a program error is generated and then data is read to a program protection area of the RAM(200), the memory protection unit(300) generates a memory write error signal by receiving an alarm message from the CPU(100). That is, the memory protection unit(300) performs the function of protection of the memory by applying a high signal to a CS(Chip Select) terminal existing in the RAM(200). When the CS terminal is high, the RAM(200) becomes a non-activation state, thereby capable of protecting the program area of the RAM(200).
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