1300 Henley Court Pullman, WA 99163 509.334.6306 www.digilentinc.com PmodDA3 Reference Manual Revised April 12, 2016 This manual applies to the PmodDA3 rev. B Overview The PmodDA3 is a 16-bit digital-to-analog converter (DAC) with an SMA connector for high resolution and low noise analog output. Features include: High resolution, 16-bit Digital-to-Analog converter Low noise analog output SMA connector 2.5V reference voltage Small PCB size for flexible designs 1.2 0.8 (3.0 cm 2.0 cm) 6-pin Pmod port with GPIO interface Follows Digilent Pmod Interface Specification Type 1 The PmodDA3. 1 Functional Description The PmodDA3 utilizes Analog Devices AD5541A to provide analog output with 16-bit resolution. 2 Interfacing with the Pmod The PmodDA3 communicates with the host board via a SPI-like protocol. This interface is different than the traditional SPI protocol in the fact that the pin normally designated to the host receiving data (MISO), is now used for a Load DAC (LDAC) function so that the output of the DAC can be updated immediately once the module is loaded with the incoming 16 bits of data. To send data to the Pmod, users must drive the Chip Select (CS) line to a logic level low voltage and then send the 16 clock pulses and 16 bits of data in SPI Mode 0 that is, placing the most significant bit (MSB) of data on the data line right after the Serial Clock line (SCLK) has been brought to a logic level low voltage. When all of the data has been latched into, i.e. prepared for, the internal serial input register, bringing the CS line back to a logic level high voltage will transfer all of the data from the shift register to the serial input register if Copyright Digilent, Inc. All rights reserved. DOC : 502-241 Page 1 of 2 Other product and company names mentioned may be trademarks of their respective owners. PmodDA3 Reference Manual LDAC is at a high voltage state. Pulsing the LDAC pin low and then high will asynchronously transfer all of the data into the DAC register, resulting in the appropriate analog voltage on the SMA connector. Alternatively, users may hold the LDAC pin at a logic level low voltage when bringing the CS pin high to directly transfer the data from the shift register to the DAC register. Pin Signal Description 1 ~CS Chip Select 2 DIN Data Input 3 ~LDAC LOAD DAC 4 SCLK Serial Clock 5 GND Power Supply Ground 6 VCC Power Supply (3.3V/5V) Table 1. Pinout description table. Any external power applied to the PmodDA3 must be within 2.7V and 5.5V however, it is recommended that the Pmod is operated at 3.3V. 3 Physical Dimensions The pins on the pin header are spaced 100 mil apart. The PCB is 1.2 inches long on the sides parallel to the pins on the pin header and 0.8 inches long on the sides perpendicular to the pin header. Copyright Digilent, Inc. All rights reserved. Page 2 of 2 Other product and company names mentioned may be trademarks of their respective owners.