| 摘要 |
PROBLEM TO BE SOLVED: To make a boot program changeable even after storing a flash memory to a printed circuit board. SOLUTION: In a system provided with an external flash memory 2 and an RAM 3 at a microcomputer 1, a secondary boot program for changing the boot program is prepared in a firmware program of the flash memory, and the secondary boot program is operated by setting at the reset of the system. The boot program is transferred to the RAM through an external storage device 4 or a transmission interface 5, and after erasing the boot program of the flash memory, the boot program on the RAM is written in the flash memory. In the case a joint test action group (JTAG) is used, a change is made by transferring the boot program and the firmware program from an incircuit emulator to the RAM. COPYRIGHT: (C)2004,JPO
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