User manual

Basys MX3™ Board Reference Manual
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Page 37 of 56
 Configuration functions are implemented for each servo. These functions configure OC5RS or OC4RS
according to the desired duty.
If users want to control the servos without the SRV library, they must implement their own servo control
functionality.
15.3 Shared Pins
As you can see from the schematic, the S0_PWM signal shares the same PIC32 pin with BTNR and the S1_PWM
signals shares the same PIC32 pin with BTND (see User Buttons). These buttons should not be used in designs that
are also using servos.
16 IrDA Module
Basys MX3 features an onboard FIR-compatible IrDA module. The part used is the ROHM Semiconductor RPM973-
H11. The RPM973-H11 is a high-performance IrDA module that integrates an infrared remote control transmission
function and a high-speed (4Mbps) FIR-compatible IrDA module. It features an LED for transmitting and a PIN
photo diode for receiving.
Figure 16.1. IrDA schematic diagram.
The PIC32 communicates with the IrDA module via two pins (named from PIC32 perspective): IR_TX, connected to
the TXD pin of the RPM973 and used for transmitting over IRDA, and IR_RX, connected to the RXD pin of the
RPM973 and used for receiving data over IrDA. Also, an IR_PDOWN signal, connected to the PWDOWN pin of the
RPM973, is used by the microcontroller to enable (0 value) or disable (1 value) the module.
When TXD (IR_TX) is 1, the transmitting LED of the RPM973 module is lit. When the PIN photo diode detects light,
it outputs 1 on RXD (IR_RX).
16.1 Connectivity
The following table shows the signals connecting the IRDA module to the PIC32:
Name
PIC32 pin
IRDA module pin
IRDA_PDOWN
RPG1/PMD9/RG1
PWDOWN/Mode