IC card having system ROM selection inhibit

Details IC card having system ROM selection inhibit IC card having system ROM selection inhibit

1988-12-01

1991-05-14

Williams, Jr., Archie E.

Boots, shoes, and leggings

3649218, 364938, 3649283, 3649284, 3649278, 3649261, 3649263, 364964, 3649446, 364954, 3649542, 364468, 36494492, 3649655, 364969, 364243, 3642343, 364234, 3642446, 3642217, 364221, 3642384, G06F 1206, G06F 1128

Patent

active

050162128

ABSTRACT:
An IC card has a CPU, a first memory for storing a test program, a second memory for storing an application progam, a bus connecting the CPU and the first and second memories. A detection circuit for detecting whether the CPU has began executing the application program stored in the second memory, and a disconnection circuit for disconnecting the first memory from the bus when the detection circuit detects that the CPU has begun executing the application program. The above-described arrangement makes it impossible to access the test program in the system ROM from the application program thereby preventing the occurrence of incorrect access.

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