Digilent PmodAD5TM Analog to Digital Voltage Converter Revision: January 24, 2013 Note: This document applies to REV A of the board 1300 Henley Court | Pullman, WA 99163 (509) 334 6306 Voice and Fax Overview The PmodAD5 is a high resolution analog-todigital converter built around the Analog Devices AD7193 Sigma-Delta ADC. Features include: * * * * * * * SPI communication interface 24-bit resolution fast settling filter conversion synchronization five filter options four differential analog inputs or eight pseudo-differential inputs two SMA connector inputs Functional Description The PmodAD5 has ten analog inputs that correspond to eight data lines. The two SMA female connectors route to inputs one and two, while eight standard female header pins route to inputs one through eight. Customers can set the PmodAD5 into single or continuous conversion mode. The PmodAD5 powers up by default in continuous conversion mode. You can set the mode to start a conversion by either writing to the appropriate registers or on the rising edge of SYNC. Note: Please see the AD7193 data sheet, available from www.analog.com, for more detailed information on controlling the A/D Converter. Serial Interface The PmodAD5 has a 4-wire SPI communication interface. (See Table 1 for signal descriptions.) Doc: 502-243 Analog Inputs The analog inputs (AIN) on the PmodAD5 are configurable as four differential inputs or as eight pseudo-differential inputs. AINCOM serves as a common reference for AIN channels 1 through 8 under the eight pseudodifferential input configuration setting. When operating the PmodAD5 analog inputs as four differential inputs, the adjacent inputs correspond to positive and negative differential signals. For example, AIN1/ AIN2 represent one positive/negative differential pair and AIN3/AIN4 represent the second positive/negative differential pair. Connectors J5 and J6 are SMA female analog inputs that correspond to AIN1 and AIN2 respectively. Reference Supply and GPO The PmodAD5 has a maximum of four general purpose output (GPO) signals. Operators can access these signals from headers J2 or J3. Please see Table 1 for signal descriptions. GPO pins 1 and 0 also correspond to REFIN2+ and REFIN2-. These pins can be configured to supply the conversion/calibration reference voltage for the PmodAD5. page 1 of 2 Copyright Digilent, Inc. All rights reserved. Other product and company names mentioned may be trademarks of their respective owners. PmodAD5 Reference Manual The PmodAD5 uses the 2.5VDC reference present on REFIN1+ and REFIN2- by default. Bridge Power Down Switch Note: Please see the PmodAD5 schematic, available from www.digilentinc.com, for more detailed information on GPO and Reference Supply routing. Operators can use the bridge power down switch to control external circuitry driving the analog inputs. Closing this "switch" internally ties the BPDSW signal to ground. Synchronization Analog Supply Voltage Setting the SYNC pin to a logic low puts the PmodAD5 in a standby state. Once you set the pin to logic high, the PmodAD5 will begin gathering samples. The conversion mode (either single or continuous) must be set previously. Customers can connect an analog supply voltage at header J4, if JP1 remains open. You must keep this external voltage between 3.0V and 5.25V to avoid damaging your device. Connector Pin # Pin Name Description J1-01 J1-02 J1-03 J1-04 J1-05 J1-06 J2-01 J2-02 J2-03 J2-04 J2-05 J2-06 J2-07 J2-08 CS DIN DOUT/RDY SCLK GND DVDD AIN1 AIN2 AIN3 AIN4 AIN5 AIN6 AIN7 AIN8 J2-09 AINCOM J2-10 J2-11 J2-12 J3-01 J3-02 J3-03 J4-01 J4-02 J5 J6 REFIN2+/P1 REFIN2-/P0 BPDSW SYNC P2 P3 AVDD GND AIN1 AIN2 SPI Chip Select. Connect to host ~SS SPI Data In. Connect to host SDO SPI Data Out. Connect to host SDI SPI Clock. Connect to host SCK Ground Digital Vdd Analog Input 1 Analog Input 1 Analog Input 1 Analog Input 1 Analog Input 1 Analog Input 1 Analog Input 1 Analog Input 1 Analog Input Common, used for pseudo differential signaling with AIN8:1 Positive Reference Input/GPO1. Negative Reference Input/GP0. Bridge Power Down Switch. Synchronization control GPO2 GPO3 Analog Vdd Ground SMA input 1 SMA input 2 Table 1. Connector Pinout Tables www.digilentinc.com page 2 of 2 Copyright Digilent, Inc. All rights reserved. Other product and company names mentioned may be trademarks of their respective owners.