ADS1278EVM Hardware Details
Analog input sources (Channels 5-8) are connected directly to J1. These inputs can be filtered by
installing passive components in the option filter circuitry. By default, the resistors are populated with 0
Ω
resistors and the capacitors are not installed. No circuitry is provided to buffer these signals before
connecting to the converter.
Table 6. J3: Primary Analog Interface Pinout
Description
Signal
Pin Number
Signal
Description
Analog Input Channel 4 Negative
ANN4
J3.1
(1)
J3.2
ANP4
Analog Input Channel
4 Positive
Analog Input Channel 3 Negative
ANN3
J3.3
J3.4
ANP3
Analog Input Channel
3 Positive
Analog Input Channel 2 Negative
ANN2
J3.5
J3.6
ANP2
Analog Input Channel
2 Positive
Analog Input Channel 1 Negative
ANN1
J3.7
J3.8
ANP1
Analog Input Channel
1 Positive
Analog Ground
AGND
J3.9
J3.10
Not Connected
Not used for this
design
Analog Ground
AGND
J3.11
J3.12
Analog Ground
AGND
Analog Ground
AGND
J3.13
J3.14
Not Connected
Not used for this
design
Not used for this design
Not Connected
J3.15
J3.16
Not Connected
Not used for this
design
Analog Ground
AGND
J3.17
J3.18
EXTREFN
External Reference
negative input
Analog Ground
AGND
J3.19
J3.20
EXTREFP
External Reference
positive input
(1)
Pin 1 is top left-hand corner, located next to reference designator.
Table 7. J1: Secondary Analog Interface Pinout
Description
Signal
Pin Number
Signal
Description
Not used for this design
Not Connected
J3.1
(1)
J3.2
Not Connected
Not used for this
design
Analog Input Channel 8 Negative
ANN8
J3.3
J3.4
ANP8
Analog Input Channel
8 Positive
Analog Input Channel 7 Negative
ANN7
J3.5
J3.6
ANP7
Analog Input Channel
7 Positive
Analog Input Channel 6 Negative
ANN6
J3.7
J3.8
ANP6
Analog Input Channel
6 Positive
Analog Input Channel 5 Negative
ANN5
J3.9
J3.10
ANP5
Analog Input Channel
5 Positive
(1)
Pin 1 is top right-hand corner, located next to reference designator.
5.5
Digital Interface
The digital signals are controlled via DSP interface or I
2
C ICs on the EVM. Some of the digital control pins
allow control via hardware or software methods. See
for details on these pins and their
operation. The digital control signals can be applied directly to the EVM or by connecting the EVM to a
DSP or micro controller interface board, such as the MMB0 if purchased as part of the
ADS1278EVM-PDK, the
or
boards which are available from Texas
Instruments. For a list of compatible interface and/or accessory boards for the EVM or the ADS1278, see
the relevant product folder on the TI web site.
5.5.1
Digital Format Control
The ADS1278 allows the serial interface to be used in two different formats: an SPI-compatible mode and
a frame-sync format. Switch S6 switches between these two formats:
•
SPI format configures the signals as follows:
13
SBAU197
–
February 2012
ADS1x7xEVM-PDK
Copyright
©
2012, Texas Instruments Incorporated
