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Texas Instruments Modular Evaluation Module MSOP8 User Manual

Page 18

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Analog Input

5-2

5.1

Analog Input

The analog input source can be applied directly to J1 (top or bottom side) or
through optional amplifier and signal conditioning modules. The analog input
range is dependent on the configuration of the EVM and the ADC installed at
location U1. Consult the datasheet for the device to determine the maximum
analog input range.

5.2

Digital Control

The digital control signals can be applied directly to J2 (top or bottom side).
The modular MSOP8 EVM can also be connected directly to a DSP or a micro
controller interface board, such as the HPA449. See the product folder for the
EVM or the installed device for a current list of compatible interface and/or
accessory boards.

5.3

Chip Select (Shut Down)

Jumper JMP2 is provided to allow the selection of the signals applied to the
chip select (/CS) or shutdown (SHDN) pin of the ADC installed on the EVM.
The factory default condition for the EVM is to place a shunt jumper between
pins 1 - 2 of JMP2. This allows the Frame Sync (FS) signal from DSP host
systems to be used as a chip select for the ADC. This signal originates from
J2.7. When JMP2 is moved to pins 2 - 3, the /CS (SHDN) signal is applied via
J2.1.

5.4

Digital I/O Buffers

Single gate buffers U3, U5 and U6 are provided to ensure the safe operation
of the modular MSOP8 EVM with low voltage host controllers. The digital I/O
voltage applied to these buffers via JMP3 should be set in accordance with the
operating voltage of the host controller.

5.5

Default Jumper Locations

Table 5 - 1 provides a list of jumpers found on the EVM and their factory default
conditions.

Table 5 - 1. List of Jumpers

Jumper

Shunt Position

Jumper Description

JMP1

Pins 1 - 2

Controls ADC Supply Voltage (default is +5Va Source)

JMP2

Pins 1 - 2

Controls ADC /CS(SHDN) Pin (default is FS from DSP Host)

JMP3

Pins 5 - 6

Controls Digital I/O Voltage (default is +3.3Vd Source)

JMP4

CLOSED

Ties ANALOG and DIGITAL grounds together

JMP5

Pins 1 - 2

Controls External Ref. Source (default is +2.5V from U2)

JMP6

Pins 1 - 2

Controls REFERENCE Source to ADC (default is onboard reference/buffer
circuit)