Patent ID: 6388415
Filing Date: 2002-05-14
Classification: G05B

Abstract:
A method for controlling a step motor of a scanner, wherein the scanner includes a microcontroller, a memory buffer and an image-sensing module, the micro-controller having a CB (count base) register, a PCN (pulse count number) register, an MCSI (motor constant speed interval) register, a TCB (temporary count base) register, a BA (base accumulator) register and a clockwise rotation flag, said method comprising the steps of:generating a reference pulse in response to an extended oscillatory signal; generating a synchronous trigger signal in response to each exposure trigger signal generated by the image-sensing module and clearing the BA register; accumulating the BA register by adding the value of the CB register in response to the reference pulse; generating an asynchronous trigger signal and clearing the BA register when the BA register is greater than or equal to the PCN register; and enabling a back-tracking control when the memory buffer is full.