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PmodAD1™ Reference Manual
Revised April 15, 2016
This manual applies to the PmodAD1 rev. G
DOC#: 502-064
Copyright Digilent, Inc. All rights reserved.
Other product and company names mentioned may be trademarks of their respective owners.
Page 1 of 2
Overview
The Digilent PmodAD1 is a two channel 12-bit analog-to-digital converter that features Analog Devices AD7476A.
With a sampling rate of up to 1 million samples per second, this Pmod is capable of excelling in even the most
demanding audio applications.
1 Interfacing with the Pmod
The PmodAD1 communicates with the host board via an SPI-like communication protocol. The difference between
the standard SPI protocol and this protocol is manifested in the pin arrangement on this Pmod. A typical SPI
interface would expect a Chip Select, a Master-Out-Slave-In, a Master-in-Slave-Out, and a Serial Clock signal.
However, with the two ADCs on this chip, both of the data lines (MOSI and MISO) are designed to operate only as
outputs, making them both Master-In-Slave-Out data lines.
The PmodAD1 will provide its 12 bits of information to the system board through 16 clock cycles with first four bits
consisting of four leading zeroes and the remaining 12 bits representing the 12 bits of the data with the MSB first.
The first leading zero is clocked out on the falling edge of the CS signal with all of the subsequent bits clocked out
on the falling edge of the serial clock signal.
The PmodAD1.
Two channel 12-bit analog-to-digital
converter
Simultaneous A/D conversion at up to one
MSa per channel
Two 2-pole Sallen-Key anti-alias filters
Small PCB size for flexible designs 0.95 in ×
0.8 in (2.4 cm × 2.0 cm)
6-pin Pmod port with GPIO interface
Library and example code available in
resource center
Features include:
PmodAD1™ Reference Manual
Copyright Digilent, Inc. All rights reserved.
Other product and company names mentioned may be trademarks of their respective owners.
Page 2 of 2
A pinout table and diagram for the PmodAD1 are provided below:
Any external power applied to the PmodAD1 must be within 2.35 to 5.25 volts to ensure that all of the
components in the PmodAD1 work correctly.
2 Physical Dimensions
The pins on the pin header are spaced 100 mil apart. The PCB is 0.95 inches long on the sides parallel to the pins on
the pin header and 0.80 inches long on the sides perpendicular to the pin header.
Header J1
Pin
Signal
Description
1
CS
Chip Select
2
D0
Input Data 1
3
D1
Input Data 2
4
SCK
Serial Clock
5
GND
Power Supply Ground
6
VCC
Power Supply (3.3V/5V)
Header J2
Pin
Signal
Description
1
A0
Input Data 1
2
GND
Power Supply Ground
3
A1
Input Data 2
4
GND
Power Supply Ground
5
GND
Power Supply Ground
6
VCC
Positive Power Supply
Table 1. Pin descriptions as labeled on the PmodAD1.
Figure 1. AD1 circuit diagram.
