The invention relates to an operation method of a configuration interface of a
microcontroller, comprising the follow steps: when a high level is input into a testing port, a serial
clock and a serial data are input through an I / O port, the serial data is compared with an operation
method code which is internally set, a corresponding operation method can be accessed through the comparison of the effect. The invention also comprises a function testing operation method, a DC parameter testing operation method, a digit / analog conversion testing operation method, a program storage testing operation method, a parallel
programming mode operation method and a serial
programming mode operation method. The configuration interface operation method of the invention can be scalable, and can access a plurality of testing operation methods and working methods, the access of a
chip to different testing or working operation methods becomes more easy.