Digilent 410-292P-KIT - Manual (Page 21)

Nexys4 DDR™ FPGA Board Reference Manual
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Page 21 of 29
11 Pmod Connectors
The Pmod connectors are arranged in a 2x6 right-angle, and are 100-mil female connectors that mate with
standard 2x6 pin headers. Each 12-pin Pmod connector provides two 3.3V VCC signals (pins 6 and 12), two Ground
signals (pins 5 and 11), and eight logic signals, as shown in Figure 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
5.
Pin 1
Pin 12
Pin 6
8 signals VCC GND
Figure 20. PMOD connectors; front view, as loaded on PCB.
Pmod JA Pmod JB Pmod JC Pmod JD Pmod XDAC
JA1: C17 JB1: D14 JC1: K1 JD1: H4
JXADC1: A13 (AD3P)
JA2: D18 JB2: F16 JC2: F6 JD2: H1 JXADC2: A15 (AD10P)
JA3: E18 JB3: G16 JC3: J2 JD3: G1
JXADC3: B16 (AD2P)
JA4: G17 JB4: H14 JC4: G6 JD4: G3 JXADC4: B18 (AD11P)
JA7: D17 JB7: E16 JC7: E7 JD7: H2
JXADC7: A14 (AD3N)
JA8: E17 JB8: F13 JC8: J3 JD8: G4 JXADC8: A16 (AD10N)
JA9: F18 JB9: G13 JC9: J4 JD9: G2
JXADC9: B17 (AD2N)
JA10: G18 JB10: H16 JC10: E6 JD10: F3 JXADC10: A18 (AD11N)
Table 5. Nexys4 DDR Pmod pin assignments.
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, as well as other functions. See
www.digilentinc.com for more information.
11.1 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 of 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 Nexys4 DDR 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 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