一种基于74HC595产生舵机用多路PWM波的方法

利用MSP430和74HC595产生了类人机器人舵机用的48路PWM波,且仅需占用MSP430单片机的P5端口,为机器人的其他控制电路保留了足够的单片机I/O口.硬件电路的特色是采取每片74HC595的串行输入端并联在一起,虽然任意时刻每片74HC595的串行输入数据相同,但输入的串行数据是否会从并行输出端输出还取决于各自的锁存脉冲.软件算法则应用了分时复用思想,串行数据按8组分时输入,每组含6路数据.该电路及其软件算法也适用于51系列、AVR系列单片机,是中低速单片机控制多路舵机的有效方案.

Study on Producing Multiplex PWM Waves for Driving Servos Using 74HC595

With the application of I/O port P5 of MSP430 and six chips of 74HC595, 48-channel PWM waves can be produced for the driving servos of humanoid robot, thus leaving enough I/O ports for collecting signals from sensors, sending commands, et al. The character of this circuit is that these chips of 74HC595 are connected in general serial mode, but whether serial input data could be sent to their output ports or not would be still decided by the latch clock pulse of each 74HC595. Furthermore, the idea of time split multiplexing is used in program- ming. There are 48 serial data entered to these chips of 74HC595 by eight groups in different time of a cycle, and every time only 6 data can be sent to their output ports. This method is also suitable for MCU such as 51 and AVR series, an effective programme for the control of multi-channel actuators by single-chips.