1 dual analog/digital pmod – Digilent 410-183P-KIT User Manual
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Basys3™ FPGA Board Reference Manual
Digilent produces a large collection of Pmod accessory boards that can attach to the Pmod expansion connectors
to add ready-made functions like A/Ds, D/As, motor drivers, sensors, and other functions.
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for more information.
9.1 Dual Analog/Digital Pmod
The on-board Pmod expansion connector, labeled “JXADC”, is wired to the auxiliary analog input pins of the FPGA.
Depending on the configuration, this connector can be used to input differential analog signals to the analog-to-
digital converter inside the Artix-7 (XADC). Any or all pairs in the connector can be configured either as analog
input or digital input-output.
The Dual Analog/Digital Pmod on the Basys3 differs from the rest in the routing of its traces. The eight data signals
are grouped into four pairs, with the pairs routed closely coupled for better analog noise immunity. Furthermore,
each pair has a partially loaded anti-alias filter laid out on the PCB. The filter does not have capacitors C33-C36. In
designs where such filters are desired, the capacitors can be manually loaded by the user.
NOTE: The coupled routing and the anti-alias filters might limit the data speeds when used for digital signals.
The XADC core within the Artix-7 is a dual channel 12-bit analog-to-digital converter capable of operating at 1
MSPS. Either channel can be driven by any of the auxiliary analog input pairs connected to the JXADC header. The
XADC core is controlled and accessed from a user design via the Dynamic Reconfiguration Port (DRP). The DRP also
provides access to voltage monitors that are present on each of the FPGA’s power rails, and a temperature sensor
that is internal to the FPGA. For more information on using the XADC core, refer to the Xilinx document titled “7
Series FPGAs and Zynq-7000 All Programmable SoC XADC Dual 12-Bit 1 MSPS Analog-to-Digital Converter.”
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