Pulse Width Modulated DC Motor Driver Outputs
Grove connectors J6 and J7 are con>gured for controlling DC motors.
The Raspberry Pi microcomputer supports two hardware PWM outputs: PWM0 and
PWM1, each of which can be mapped to several GPIO pins. The following device
tree overlay command must be appended to /boot/config.txt to con>gure the
Raspberry Pi PWM subsystem for the MUNTS-0018 Tutorial I/O Board:
dtoverlay=pwm-2chan,pin=12,func=4,pin2=19,func2=2
Pin Mapping
J6 Pin 1 PWM0 PWM Duty Cycle
J6 Pin 2 GPIO13 Direction
J7 Pin 1 PWM1 PWM Duty Cycle
J7 Pin 2 GPIO18 Direction
Other PWM pin con>gurations are possible. With no PWM device tree overlay at
all, J2, J3, J6, and J7 are just mapped to GPIO pins. It is also possible to map
both PWM outputs to one Grove Connector, for motor driver circuits that require
clockwise and counterclockwise speed signals instead of speed and direction.
See the Raspberry Pi device tree overlay documentation for more information
about the possible PWM output con>gurations.
Alternate PWM Device Tree Overlay Command for Cytron MD13S
The Grove Connector on the Cytron MD13S motor driver has the speed and
direction signals swapped: DIR is connected to pin 1 (yellow) and PWM is
connected to pin 2 (white).
The following device overlay command con>gures J6 and J7 for compatibility with
the MD13S:
dtoverlay=pwm-2chan,pin=18,func=2,pin2=13,func2=4
Pin Mapping
J6 Pin 1 GPIO12 Direction
J6 Pin 2 PWM1 PWM Duty Cycle
J7 Pin 1 GPIO19 Direction
J7 Pin 2 PWM0 PWM Duty Cycle
Note: This overlay command makes the servo headers unusable for servos.
MUNTS-0018 Raspberry Pi Tutorial I/O Board User Guide Page 5 of 11
