Patent ID: 7979736

Claim:
A method for updating a nonvolatile memory having a memory block which stores a plurality of parameter data which corresponds to a plurality of parameters for controlling operation of a low-order device and which is capable of being updated by a command from a high-order device, and error detection data for detecting whether the plurality of parameter data is correct or not, wherein one of the plurality of parameter data is to be updated to a specified parameter data, said method comprising the steps of a first step in which the memory block including the one parameter data to be updated is read to a working area from the nonvolatile memory on a basis of a parameter updating command from the high-order device; a second step which detects whether the plurality of parameter data in the memory block that is read through the first step is correct or not on a basis of the error detection data; a third step which is executed when an error is detected in the second step to generate temporary updating data, which are not initial values in the memory block, in the working area by updating the one parameter data to be updated to the specified parameter data and by updating data except the one parameter data to be updated to an unspecified data; a fourth step which is executed when the error is not detected in the second step to generate normal updating data in the working area by updating only the parameter data to be updated to the specified parameter data; a fifth step in which the temporary updating data generated through the third step or the normal updating data through the fourth step are written into the nonvolatile memory; and a sixth step which is executed after the fifth step has been finished to notify the high-order device of having finished of the parameter updating.