DC Motor Plug¶
The DC Motor Plug is a small board containing two H-bridges to drive small DC motors or a stepper.
The board uses an I2C I/O expander to support the two motor drivers as well as 4 freely available I/O pins.
The motor drivers are based on the TC4424 chip, which is mainly intended for driving MOSFET chips, but which happens to also work well to drive small motors forward or backward. Motors with stall currents up to about 1.5A @ 4.5..18V should work just fine.
An I2C bus running at 3.3V is used for I/O, with all the power and signal lines brought out to to both sides of the board to allow daisy-chaining with other I2C-conformant boards.
There is one solder jumper to configure each plug for one of the following 7-bit I2C addresses:
Dimensions: 21.1 x 34.0 mm
CadSoft EAGLE design files: see below.
This plug can be operated at 5V as well as 3.3V.
This board uses the conventions of a JeePlug and can be used with the ports on a JeeNode. It can also be used with other boards and MCU’s, if you hook it up properly and adapt the interface code for it.
N.B. the V- pin is left floating to avoid ground loops but it is not intended to be significantly different from the GND used by the chips and the I2C bus. The recommendation is to strap it to GND. A ferrite bead on the strap can reduce switching noise injected back into the logic GND. Chips will fry if you do not reference V- to GND.