7/30/2019
Basys MX3 Reference Manual [Reference.Digilentinc]
https://reference.digilentinc.com/reference/microprocessor/basys-mx3/reference-manual?_ga=2.68739409.1349070004.1564406803-1961480359.…
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The control of the IrDA module is implemented in the IrDA library of the Basys MX3 library pack. Library features include:
IRDA_PDOWN is used as a basic digital output pin.
IRDA communication signals are mapped over the UART5 communication signals:
U5RXR = 0x05; // IR_RX (RB6) -> U5RX
RPB7R = 0x04; // IR_TX (RB7) -> U5TX
UART5 interface is configured in the IrDA mode (the IREN bit is set) with 9600 baud and used for sending and receiving data to
IrDA module.
The Basys MX3 contains an audio out module, controlled by the PIC32 using the digital signal A_OUT. This digital signal is PWM
controlled to generate multiple values between 0 and 3.3 V. A PWM signal is a chain of pulses generated at fixed frequency, with each pulse
potentially having a different width. This digital signal can be passed through a simple low-pass filter that integrates the digital waveform to
produce an analog voltage proportional to the average pulse-width over some interval (the interval is determined by the cut-off frequency of
the low-pass filter and the pulse frequency). For example, if the pulses are high for an average of 10% of the available pulse period, then an
integrator will produce an analog value that is 10% of the Vdd voltage, in this case 0.33 V. Figure 17.2 shows a waveform represented as a
PWM signal.
The volume of the output audio signal can be adjusted using a thumbwheel potentiometer labeled SPEAKER VOLUME, situated in the top
left corner of the board.
The generated audio out signal is outputted to an onboard speaker through a 1.2W audio power amplifier (IS31AP4991) and to an onboard
headphones connector, labeled LINE OUT. When headphones are connected to the LINE OUT port, the onboard speaker is automatically
muted.
16.2. Functionality
17. Audio Out
17.2. Connectivity
