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5 EVM Operation
5.1 Analog Input
5.2 Digital Control
5.3 Default Jumper Locations
6 Kit Operation
6.1 ADS7845EVM-PDK Block Diagram
EVM Operation
The following section provides information on the analog input, digital control, and general operating
conditions of the ADS7845EVM.
The analog input sources (touch screen and auxiliary input) can be applied directly to J1 (top side or
bottom side) or through signal-conditioning modules available for the modular EVM system.
The digital control signals can be applied directly to J2 (top side or bottom side). The modular
ADS7845EVM can also be connected directly to a DSP or microcontroller interface board, such as the
HPA449, or to the USB-MODEVM Interface Board if purchased as part of the ADS7845EVM-PDK. For a
current list of compatible interface and/or accessory boards for the EVM or the ADS7845, see the relevant
product folder on the TI web site .
Table 4 provides a list of jumpers found on the EVM and the factory default conditions for each one.
Table 4. List of Jumpers
Jumper Shunt Position Jumper Description
JMP1 3-4 Selects reference voltage source to ADS7845. 1-2 selects VCC, 3-4 selects the
onboard 2.5V reference, and 5-6 selects the external reference voltage from J1.20.
JMP2 CLOSED Connects analog ground (AGND) to digital ground (DGND).Default is connected.
JMP3 CLOSED EEPROM Address Select - when installed and used with the USB-MODEVM, firmware
for the motherboard is executed from the EEPROM on board the ADS7845EVM. This
is the default mode.
JMP4 5-6 Analog Power Select (default is +5VA)
The following section provides information on using the ADS7845EVM-PDK, including setup, program
installation, and program usage.
A block diagram of the ADS7845EVM-PDK is shown in Figure 1 . The evaluation kit consists of two circuit
boards connected together. The motherboard is designated as the USB-MODEVM Interface Board, while
the daughtercard is the ADS7845EVM described previously in this manual.
SBAU122 – March 2006 ADS7845EVM and ADS7845EVM-PDK 5
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