User manual
Basys MX3™ Board Reference Manual
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Page 32 of 56
The Basys MX3 provides a USB to UART serial converter, via a micro-USB connector and uses UART_TX and
UART_RX pins of the PIC32. These 2 pins can be mapped to implement UART4 or UART5 functionality. See
Remappable pins section for more details about remapping.
Besides the UART port mapped to the USB_UART interface, other UART interfaces can be mapped to the Pmod’s
pins, depending on the remappable functionality available. See Pmod Connectors for more details.
13.1 Connectivity
The following table shows the signals that go to the USB-Serial module from PIC32.
Name
PIC32 pin
UART_TX
RPF12/RF12
UART_RX
RPF13/RF13
Table 13.1. UART connectivity.
The UART_TX must be defined as digital output and the UART_RX as a digital input:
TRISFbits.TRISF12 = 0; //RF12 (UART_TX) set as an output
TRISFbits.TRISF13 = 1; //RF13 (UART_RX) set as an input
13.2 Functionality
The USB-UART converter module functionality is implemented in the UART library of the Basys MX3 library pack.
Implementation features:
USB-UART converter signals are mapped over the UART4 communication signals:
o U4RXR = 0x09; // UART_RX (RF13) -> U4RX
o RPF12R = 0x02; // UART_TX (RF12) -> U4TX
Send and receive functions over UART are implemented in the library.
If the users want to use the UART module without the UART library, they need to implement their own UART
functionality.
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.