| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To prevent imitation and internal operation analysis of program data of a system using a programmable device. <P>SOLUTION: As shown in a block diagram of the system using the programmable logic device, a ROM 11 is external memory means for storing program data used by the programmable logic device 10, and the programmable logic device 10 comprises I/O controlling means 12 for reading in states of input/output pins as key information generating means, decoding means 13 for decoding data from the ROM 11 with key information from the I/O controlling means 12 to output decoded program data, a logic element array 15 having arrayed logic elements whose function is defined when setting data are written into an internal rewritable memory, and programming means 14 for writing into the logic element array 15. <P>COPYRIGHT: (C)2004,JPO</p> |
