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10.7 UCN-5804 stepper motor controller chip

UCN-5804
Figure 10.7 is a schematic pin-out of the UCN-5804. This inte-
grated circuit (IC) is designed to control and drive a four-phase
unipolar stepper motor, such as the one we are using. Features of
the UCN-5804 are as follows:
1.25-ampere (A) maximum output current (continuous)
35-volt (35V) output sustaining voltage 219
Full-step and half-step outputs
Output enable and direction control
Internal clamp diodes
Power-on reset
Internal thermal shutdown circuitry
The IC has a continuous output rating of 1.25 A per phase at a
maximum voltage of 35 V. This is more than enough power to run
our 12V stepper motor. The current required per phase (12 V/110
ohms 0.11 A) is about one-tenth of an ampere.
The UCN-5804 internal logic sequences its output pins in time
with a square wave pulse delivered to pin 11. Each square wave
pulse (high to low transition) delivered to this pin increments the
stepper motor sequence.

When you reach the end of your table, the sequence repeats starting
from the top of the table. To reverse the stepper motor direction,
start the sequence from the bottom and work toward the top.
Pin 15 is the output enable. When this pin is held high, all outputs
on the IC are disabled (off). If this function isn’t required by your
circuit or system, this pin should be tied to ground (low).

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