NEC PD78214 - Manual (Page 424)

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16
CHAPTER 16 APPLICATION EXAMPLES
16.1 OPEN-LOOP CONTROL OF STEPPER MOTORS
This section provides an example of controlling stepper motors with the real-time output function, 8-bit timer/
counter 1, and the macro service function of the
µPD78214.
Fig. 16-1 shows the functional blocks for controlling two stepper motors.
An interrupt signal is generated when the value in 8-bit timer/counter 1 (TM1) is matched with the value in compare
register CR10 or CR11. The interrupt signal triggers a macro service in which the CPU automatically transfers table
data prepared in memory to the compare register and the buffer register for the real-time output port. Data
transferred to the compare register is used for the interval before the generation of the next interrupt.
Data transferred to the buffer register is output from port 0.
Open-loop control of stepper motors with the
µPD78214 has the following advantages:
(1) The real-time output function provides accurate control (output) signals based on a specified interval.
(2) Two stepper motors can be independently controlled with an 8-bit timer/counter and two compare registers.
Hardware can thus be efficiently used.
(3) The macro service function can perform complicated control, such as the acceleration/deceleration of stepper
motors, without the need for software.