Datasheet
The Genesys 2 features four Pmod connectors of different “styles” with subtle differences between them. Table 10
summarizes these differences.
Pmod
conector
Power Analog/Digital Routing Series
protection
Recommended usage
JXADC VADJ Dual Differential; Pairs:
1-7,2-8,3-9,4-10
100 ohm Analog inputs; LVDS_25
input/output (VADJ=2.5V)
JA, JB 3.3 V Digital-only Differential; Pairs:
1-2,3-4,7-8,9-10
0 ohm >=10MHz; LVDS_25 input
JC, JD 3.3 V Digital-only Single-ended 200 ohm <10 MHz, LVCMOS33
Table 10. Pmod differences.
JXADC is a dual digital/analog Pmod wired to auxiliary analog FPGA input pins (see description below). JA, JB, JC and
JD are digital-only but routed in a different manner. JC and JD signal traces are routed as single-ended signals with no
length matching or characteristic impedance guarantees. JA and JB connector signals, on the other hand, are routed
differentially in pairs at 100 ohm characteristic impedance. Inter-pair matching is +- 20mm. The series resistor on these
two Pmods are replaced by 0 ohm shunts, so care must be exercised not to use voltages higher than 3.3V, or short
FPGA-driven pins.
For slow digital signals, below 10 MHz, all Pmod connectors are equivalent, if VADJ is set to 3.3 V (see the Power
Supplies section). For higher frequencies, the routing and series protection need to be taken into account as well.
Pmod Pinouts
JA1: B13 JB1: G14 JC1: K2 JD1: JXADC1: A13
JA2: F14 JB2: P15 JC2: E7 JD2: JXADC2: A15
JA3: D17 JB3: V11 JC3: J3 JD3: JXADC3: B16
JA4: E17 JB4: V15 JC4: J4 JD4: JXADC4: B18
JA7: G13 JB7: K16 JC7: K1 JD7: JXADC7: A14
JA8: C17 JB8: R16 JC8: E6 JD8: JXADC8: A16
JA9: D18 JB9: T9 JC9: J2 JD9: JXADC9: B17
JA10: E18 JB10: U11 JC10: G6 JD10: JXADC10: A18
Table 11. Genesys 2 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, and other functions. See
Digilent's Pmod category
[http://store.digilentinc.com/pmod-peripheral-modules/] for more information.
14.1 Dual Analog/Digital Pmod