EVM Operation
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7.1
Usage in PDK
If using the ADS1259EVM as part of the ADS1259EVM-PDK, switch S4 should be set to the left, using the
multiplexer output. Using the onboard 7.3728MHz crystal oscillator allows the ADS1259EVM-PDK
software to recognize the EVM using the software provided.
7.2
Usage as a standalone EVM
If using the EVM in your own system and not with the PDK hardware and software, switch S4 can be used
to select the clock. The switch can be used to select the 7.3728MHz crystal (through multiplexer U31) or
to allow the onboard oscillator to be enabled when S4 is set to ground.
8
EVM Operation
This section provides information on the analog input, digital control, and general operating conditions of
the ADS1259EVM.
8.1
Analog Input
A single-channel differential input source can be applied directly to J8 (top or bottom side) or through
signal-conditioning modules available for the modular EVM system. The input is connected through switch
S2 and through a low-pass filter (R1, R2, C10, C11, and C12) before reaching the ADS1259.
The common-mode voltage (VCOM) for the PGA280 input buffer is 2.5V supplied from the REFOUT of the
ADS1259, the VCOM pin at the analog header (J8.15), or a voltage divider set to AV
DD
/2. This
configuration can be selected through switch S3.
8.2
Digital Control
The digital control signals can be applied directly to J7 (top or bottom side). The modular ADS1259EVM
can also be connected directly to a DSP or microcontroller interface board, such as the
or
boards available from Texas Instruments, or the MMB0 if purchased as part of the
ADS1259EVM-PDK. For a list of compatible interface and/or accessory boards for the EVM or the
ADS1259, see the relevant product folder on the TI web site. Some of the digital signals are controlled
directly with pins on J7.
Other pins on the ADS1259 may be accessed via J7 through J2, J3, and J4. The ADS1259EVM-PDK
uses the PGA280 external chip select function to control the ADS1259; therefore, these jumpers must be
set to allow for access through J7.
10
ADS1259EVM, ADS1259EVM-PDK
SBAU163A – March 2010 – Revised April 2010
Copyright © 2010, Texas Instruments Incorporated
