Method of loading initial program in processor system

摘要

In a processor system having a CPU, a RAM, and a communication portion for external communication, the operation of the central processing unit is stopped when an IPL operation mode is selected by an operation mode selection switch. An IPL program transferred from the outside through the communication portion is then written to the RAM starting from a predetermined address, and the stoppage of the operation of the CPU is thereafter canceled. The CPU restarting the operation executes the IPL program written to the RAM by first reading the predetermined address to download a system program. Since the IPL program is transferred from the outside, the IPL program to be used can be easily changed.