| 摘要 |
PROBLEM TO BE SOLVED: To easily select the mode of a microcomputer only by providing one test terminal. SOLUTION: A test terminal 18 is connected, through a resistor 23, with 0 V, and a frequency divider 19, a shift register 20, and a mode latch circuit 21 are reset. When a high level test signal is inputted to the test terminal 18, the frequency divider 19 outputs a latch signal at the timing in which, for example, 500 clock signals are inputted from a clock terminal 16, and the shift register 20 outputs a latch signal at the timing in which 3 latch signals are outputted from the frequency-divider 19. The mode latch circuit 21 outputs a bit pattern inputted to an I/O port terminal 17 in the timing which the latch signal is outputted from the shift register 20. A decoder 22 selectively selects the mode of a microcomputer based on the bit pattern from the mode latch circuit 21. |
