Digilent 410-174P - Manual (Page 5)

USB I/O Explorer Reference Manual
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Pmod Connectors
The I/O Explorer has six Pmod connectors for
connecting Digilent Pmod peripheral modules.
There are two styles of Pmod connector: six-
pin and twelve-pin. Both connectors use
standard pin headers with 100mil spaced pins.
The six-pin connectors have the pins in a 1x6
configuration, while the twelve-pin connectors
use a 2x6 configuration. The six-pin
connectors provide four I/O signals, ground
and a switchable power connection. The
twelve-pin connectors provide eight I/O
signals, two power and two ground pins. The
twelve-pin connectors have the signals
arranged so that one twelve-pin connector is
equivalent to two of the six-pin connectors.
The power connection is switchable between
the regulated 3.3V main board supply and the
unregulated input supply.
When operating the I/O Explorer using the
factory firmware, the Pmod connectors are
accessible via a number of the API sets
provided by the Digilent Adept SDK. In addition
to the other ways that they can be used, the
I/O pins on the Pmod connectors can be
accessed for direct pin input or output using
the DPIO API functions described in the DPIO
Programmer’s Reference Manual contained in
the Digilent Adept SDK. Refer to the section
Digilent Adept Port Descriptions below for
information on the various ways that the Pmod
connectors are used.
Digilent Pmod peripheral modules can either
be plugged directly into the connectors on the
I/O Explorer or attached via cables. Digilent
has a variety of Pmod interconnect cables
available.
See the “Connector and Jumper Block Pinout
Tables” section below for more information
about connecting peripheral modules and other
devices to the I/O Explorer. These tables
describe the relationship between the various
Adept software interfaces and the signals
available on the connector pins.
Analog Inputs and Outputs
The I/O Explorer provides analog input
channels and analog output channels via
Analog to Digital (A/D) and Digital to Analog
(D/A) converters on the board. When using the
factory firmware, these analog inputs and
outputs are accessed using the DAIO API
functions provided by the Digilent Adept SDK
and described in the DAIO Programmer’s
Reference Manual.
The A/D converters for the analog input
channels are provided by the built-in A/D
converters in the two microcontrollers.
The two analog input channels accessible
through DAIO port 0 are provided by the A/D
converter in the primary microcontroller. This
port supports single sample input mode as well
as continuous sampling input mode. These two
analog input channels have input protection
diodes to protect from out-of-range input
voltages and band limiting input filters with a
cutoff frequency of 2Khz. This port supports
sample rates up to 4K samples per second.
This analog input port supports two selectable
internal voltage references (2.56V and 3.3V)
as well as an external reference that can be
applied to the AREF1 pin on connector J2.
The analog inputs for DAIO port 0 are
accessed via connectors JF and J1.
The eight analog input channels accessible
through DAIO port 1 are provided by the A/D
converter in the secondary microcontroller.
This port supports only single sample input
mode. The inputs on this port are available
using the servo connectors S1-S8. These
connectors and the corresponding I/O pins on
the microcontroller are shared between DAIO
port 0, DPIO port 6, and DEMC port 3.
This analog input port supports two selectable
internal voltage references (1.1V and 3.3V) as
well as an external reference that can be
applied to the AREF2 pin on connector J5.