| 摘要 |
PURPOSE:To rewrite a program without removing a program memory from a printed circuit board by adopting a memory whose content is rewritten through voltage application for a program memory storing an operation program so as to rewrite the program with a rewrite program. CONSTITUTION:When an operation program stored in a program memory is rewritten to revise a function of a portable telephone set 11, the telephone set 11 is connected to a rewrite unit 5 and a terminal 15-1 of a connector 15 is connected to a ground line via a terminal 53-1 of a connector 53. As a result, a mode discrimination signal of an L level is set to an input port 14-1 of a control circuit 14. When the telephone set 11 discriminates the mode to be a programming mode based on a discrimination signal whose level is logical L after initializing, a CPU 12 awaits a designation command. When the operator uses a key board 51 to enter a command, it is given to the telephone set 11 via the connector 53. The CPU 12 deletes data in a program memory 13 and writes new data supplied from the rewrite unit 5. |
