Digilent 410-274P-KIT - Manual (Page 21)

Nexys4™ FPGA Board Reference Manual
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Page 21 of 29
signals (pins 5 and 11), and eight logic signals, as shown in Fig 20. The VCC and Ground pins can deliver up to 1A of
current. Pmod data signals are not matched pairs, and they are routed using best-available tracks without
impedance control or delay matching. Pin assignments for the Pmod I/O connected to the FPGA are shown in Table
6.
Pin 1
Pin 12
Pin 6
8 signals VCC GND
Digilent produces a large collection of Pmod accessory boards that can attach to the Pmod expansion connectors
to add ready-made functions like A/D’s, D/A’s, motor drivers, sensors, and other functions. See
www.digilentinc.com for more information.
10.1 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/Digigal Pmod on the Nexys4differs 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 C60-C63. 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
Figure 20. PMOD Connectors- Front view as loaded on PCB
Pmod JA Pmod JB Pmod JC Pmod JD Pmod XDAC
JA1: B13 JP1: G14 JC1: K2 JD1: H4
JXADC1: A13
JA2: F14 JB2: P15 JC2: E7 JD2: H1
JXADC2: A15
JA3: D17 JB3: V11 JC3: J3 JD3: G1 JXADC3: B16
JA4: E17 JB4: V15 JC4: J4 JD4: G3
JXADC4: B18
JA7: G13 JB7: K16 JC7: K1 JD7: H2 JXADC7: A14
JA8: C17 JB8: R16 JC8: E6 JD8: G4
JXADC8: A16
JA9: D18 JB9: T9 JC9: J2 JD9: G2 JXADC9: B17
JA10: E18 JB10: U11 JC10: G6 JD10: F3
JXADC10: A18
Table 6. Nexys4 Pmod Pin Assignments