User Manual

Warning: SYZYGY pods are NOT hot-swappable. Connecting or disconnecting a pod from the USB104 A7 while the board is powered on may cause
damage to the pod and/or the board, and is to be avoided.
A SYZYGY Standard interface contains 16 single-ended I/O pins, 8 differential I/O pairs (which can alternatively be used as 16
additional single-ended I/O pins), and two dedicated differential clocks - one for input and one for output. Bank 15 of the FPGA is
dedicated to the Zmod port and is powered by a dedicated adjustable rail, configured by the Platform MCU as the USB104 A7 is
powered on. Template constraints for the Zmod port can be found in the USB104 A7's Master XDC file, available through Digilent's
digilent-xdc (https://github.com/Digilent/digilent-xdc) repository on Github.
Digilent provides Eclypse-compatible low-level IPs, scripted Vivado flows, and software libraries to support each
Digilent Zmod
(https://reference.digilentinc.com/reference/zmod/start). Demos are available for the Zmod ADC () and the Zmod DAC () on the USB104
A7's
Resource Center (https://reference.digilentinc.com/reference/programmable-logic/usb104a7/start).
For more information on the SYZYGY standard, see
syzygyfpga.io (https://syzygyfpga.io/).
The USB104 A7's Zmod port is compatible with a variety of different SYZYGY pods. Information required to determine if the USB104
A7 is compatible with a certain pod is summarized in Table 7.1.1:
Table 7.1.1: SYZYGY Compatibility Table
Parameter Zmod A (STD)
Port Type Standard
Single-Wide
Total 5V Supply Current 1.5A
Total 3.3V Supply Current 1.0A
VIO Supply Voltage Range 1.2V to 3.3V
Total VIO Supply Current 1.0A (VIO Group 1)
Port Groups Group 1: A
I/O Count 28 total (8 DP)
Length Matching 27 mm +- 0.2 mm (includes Artix package delay)
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7.1. SYZYGY Pod Compatibility
8. Pmod Connectors
Pmod connectors are 2×6, right-angle, 100-mil spaced female connectors that mate with standard 2×6 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 8.1. The VCC () and Ground pins can deliver up to 1A of current, but care must be taken not to exceed any of the power budgets
of the onboard regulators or the external power supply (these are described in the “Power supplies” section).
Warning: Since the Pmod pins are connected to Spartan-7 FPGA pins using a 3.3V logic standard, care should be taken not to drive these pins over 3.4V.
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.
The USB104 A7 has four Pmod connectors, some of which behave differently than others. Each Pmod connector falls into one of two
categories: standard or high-speed. Also, some Pmod connectors share their connections with the inner rows of the shield connector, and
should not be used at the same time as a shield that requires those pins. Table 8.1 specifies which category each Pmod falls into, whether
it shares any pins with the shield connector, and also lists the FPGA pins they are connected to. The following sections describe the
different types of Pmods.
Note: Some Pmods use a 1×6 pin header. Designs and IP provided by Digilent for these Pmods connect their pins to the top row of the standard 2×6 pin
interface (pins 1-4).