ing diagram for programming. When the inputs

IN1...IN4 are together Low a clock pulse is gener-

ated internally which clocks a data bit into the

shift register. If the time interval during which all

four inputs are Low is less than 0.2

µs, no clocks

pulse in generated thus preventing undesirable

programming. To generate another clock pulse at

least one of the four inputs must first go High and

then Low again. The first bit is loaded into C0 and

after 6 clock pulse it will be in the C5 posistion.

Two programming technique are suggested. The

first (Fig. 8) uses IN4 in such a way that the

power section is disabled the total programming

time (the carriage of the 6 programming bits). Fig.

9 shows another technique: the motor driving sig-

nals at the inputs IN1...IN4 are interrupted switch-

ing IN1...IN4 Low to carry a single bit. This per-

mits the motor to be enabled for the 50% of total

programming time. During the motor rotation it’s

suggested to program the device immediately af-

ter the motor phase change: this make neglect-

able the motor driving discontinuity due to the de-

vice programming.

Figure 8: Waveform for programming: the output is disabled during all the programming duration (see Table 4).

Figure 9: Waveform for programming: the output is disabled only when all four inputs are at the low level.

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