Motor Driver - Digilent Basys MX3 Reference Manual

7/30/2019
USB-UART converter signals are mapped over the UART4 communication signals:
U4RXR = 0x09; // UART_RX (RF13) -- U4RX
RPF12R = 0x02; // UART_TX (RF12) -- U4TX
Send and receive functions over UART are implemented in the library.

14. Motor Driver

The Basys MX3 features a Dual H-Bridge Motor Driver. The part used is the Texas Instruments DRV8835. It supports up to two 1.5A
brushed DC motors or one stepper motor.
The PIC32 uses 5 signals: MODE, AIN1, AIN2, BIN1, BIN2, to connect to the motor driver MODE, AIN1/APHASE, AIN2/AENBL,
BIN1/BPHASE, BIN2/BENBL control pins.
The Basys MX3 board provides a 6-pin wire-to-board terminal block that allows firm contact to the motor driver pins using a screwless,
tension clamped connector labeled MOTOR OUT (J5 on the schematic). The control signals are labeled A1, A2, B1, B2, and they
correspond to AOUT1, AOUT2, BOUT1, BOUT2 signals of motor driver.
The MODE signal selects one of the two operating modes: logic low selects IN/IN mode, while logic high selects PH/EN mode.
When using IN/IN mode, the logical values of AIN1, AIN2, BIN1, BIN2 control the 4 command signals of a stepper motor: A1, A2, B1,
B2.
When using PH/EN mode:
AIN1, AIN2 signals (through their APHASE, AENABLE functions) control the Phase (direction) and Enable of the H Bridge - the
DC motor A (outputs A1, A2) driver
BIN1, BIN2 signals (through their BPHASE, BENABLE function) control the Phase (direction) and Enable of the H Bridge - the
DC motor B (outputs B1, B2) driver.
The voltage on the output pins A1, A2, B1, B2 is dependent of the motor supply power applied to the motor controller. It is possible to use
the VBAR power pin (5V - the power from the external barrel), or an external power supplied by the user using the VEXT / GND () pins
of the MOTOR OUT connector block (0V to 11V). These two options are selectable using the MOTOR PWR jumper block (situated just
above the MOTOR OUT connector).
Using the motors with the jumper on the VBAR position requires external power source connected to the barrel power connector.
Table 14.1 details the usage of the MOTOR PWR jumper block:
Jumper
Position Description
VBAR The power provided from the external power supply (using the barrel connector) is used for motors.
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