Pololu Dual MC33926 User Manual
Page 17
PIN
Default State
Description
VIN
The connection point for the positive side of the 5 – 28 V motor power supply.
VDD
The connection point for the positive side of the logic power supply (typically 2.5
– 5 V).
VOUT
This pin gives you access to the motor power supply after the reverse-voltage
protection MOSFET (see the board schematic in
supply reverse-protected power to other components in the system, but it should
not be used for high currents. This pin should only be used as an output.
GND
Ground connection points for logic and motor power supplies. The controlling
device and the motor driver must share a common ground.
MxA/B
Output of half-bridge A/B. Each half-bridge connects to one terminal of a DC
motor.
MxPWM LOW
Pulse-width modulation input: a PWM signal on this pin corresponds to a PWM
output on the corresponding driver’s motor outputs. When this pin is low, the
motor brakes low. When it is high, the motor is on. The maximum allowed PWM
frequency is 20 kHz.
MxDIR
LOW
Motor direction input.
MxFB
Current sense output. The pin voltage is roughly 525 mV per amp of output
current. (Note that the voltage on this pin can exceed 3.3 V at high currents, which
might make it unsafe to connect to 3.3 V analog inputs. The CS circuit has a 1 kΩ
resistor in series with the output, which offers some protection, and the driver has
over-current protection that kicks in between 5 A and 8 A, so the risk is low, but
the safest approach would be to use a 3.3 V zener diode to clamp the output to
~3.3 V or a voltage divider to scale the output over a range that is appropriate.)
SF
HIGH
Diagnostic output. When both drivers are functioning normally, this pin is
internally pulled high. When a driver fault occurs, the IC drives this pin low and
the motor outputs are disabled. This pin will also be low whenever D2 is low. Note
that the status flag lines from both drivers are tied together. See
for
information on how to individually access the status flag pins (this is typically not
necessary).
D2
LOW
Disables the motor driver outputs when low. A PWM on this pin with MxPWM
held high results in drive-coast operation (vs. drive-brake when the PWM is
applied to MxPWM and D2 is held high). Toggling this pin will clear any latched
faults. Note that the disable lines from both drivers are tied together. See
for information on how to individually access the disable pins (this is typically
not necessary).
Pololu Dual MC33926 Motor Driver Shield User's Guide
© 2001–2013 Pololu Corporation
4. Using as a General-Purpose Motor Driver
Page 17 of 24