| 摘要 |
PURPOSE:To enhance the controllability of a motor by software in a stepping- motor control circuit for a facsimile apparatus or the like. CONSTITUTION:In a stepping-motor control circuit which drives a four-phase motor, a motor step-by-step advance velocity is made variable by a value set by software in a motor-status register 17, and a fundamental clock selection is software-set by a clock selector 14. In addition, data covering a plurality of lines is software-set in a data set register 16, a motor step-by-step advance pulse covering a plurality of lines is generated automatically. When the set data is continuously the same for two lines, a motor is uniform-velocity-driven at a velocity by the data, and a bit for uniform-velocity drive release use is set in a control register 23 by software. In addition, when the data set register 16 becomes empty, a CPU is informed by a hardware interrupt, and the load of the CPU is reduced until the data set register 16 by the CPU is written by DMA or software. |
