| 摘要 |
The CPU (101) prevents access an address detected by an address controller (106) following notification by the address controller, An internal memory includes a ROM (102) and RAM (103) the address controller checks whether or not the address on a bus line (111) is an address in a part of the address zones allocated to the ROM. Digital processing chip including: (a) an internal circuit (10) which contains a central processing unit CPU (101) which executes programs; an internal memory (102,103) which stores an internal program; a bus line (111) which connects the CPU to the internal memory and extends externally to transmit an address and data; a jamming section (107) at an output and input of the bus line which jams at least data taken from the address and data on the bus line, and; an external memory (20) on the exterior of a part which extends from the exterior of the bus line (111) and which stores an external program, in which is stored the; the internal circuit (10) including an address controller (106) which checks if the address on the bus line is an address in an predetermined address zone whilst the program stored in the external memory (20) is running and which informs the CPU the detection of the address in the predetermined zone
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