| 摘要 |
<p>PURPOSE:To transfer control to a ROM area including a control program by generating a jump instruction and a jump destination address or vector address on a data bus right after power-on operation. CONSTITUTION:The output of a shift register 40 is all cleared with a reset signal in the power-on operation and the data bus enters a floating state. The microprocessor generates a start address 0000 and generates a read signal when reading the data bus. At this time, the output A of the shift register 40 turns on and an inverter 50 generates jump instruction data C3 on the data bus, so that the microprocessor reads this instruction. Then, the microprocessor performs a read cycle twice to read address data FD and FF on a jump destination and moves to the address of control FFFD to execute instructions in the ROM area 31.</p> |
