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Using the DAC8881EVM with DXP

This section covers the specific operation of the DAC8881EVM-PDK. Throughout this document, the
abbreviation EVM and the term evaluation module are synonymous with the DAC8881EVM.

4.1

Hardware

The hardware consists of two main components, the first is the DAC8881EVM itself and the other is a
modular motherboard called the MMB0. The MMB0 board houses a TMS320VC5507 DSP which controls
the DAC8881 serial interface.

The hardware needs to be configured such that the DAC8881EVM is plugged onto the MMB0 aligning
female connectors P4, P2 and P6 (bottom side of the DAC8881EVM) with male connectors J4, J7 and J5
on the MMB0. Please exercise caution when assembling the boards as it is possible to misalign the
connectors. DO NOT connect the MMB0 to your PC before installing the DXP software as described in the
DXP User’s Guide! Installing the software will ensure the necessary drivers are properly loaded to run the
hardware.

Figure 11. MMB0 with DAC8881EVM Installed

4.2

MMB0 Power Supplies

Several power connections are required for the hardware to work properly. For the MMB0, the supplied 6V
AC/DC converter is all that is necessary. Please ensure J12 on the MMB0 board is closed before
connecting the AC/DC adapter to the DC In connector of the MMB0. This supply will provide all power to
the digital portion of the DAC8881EVM as well as all necessary power for the DSP. Analog power for the
DAC8881EVM must be supplied externally via J14 – a 6 position screw terminal mounted in the lower left
corner of the MMB0 board.

17

SLAU257A – September 2008 – Revised November 2009

DAC8881 Evaluation Module

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Copyright © 2008–2009, Texas Instruments Incorporated

Summary of Contents for DAC8881

Page 1: ...Jumper Settings 14 3 6 Schematics 16 4 Using the DAC8881EVM with DXP 16 4 1 Hardware 17 4 2 MMB0 Power Supplies 17 4 3 Software Running DXP 18 4 4 DAC Output Update Options 20 4 5 Data Input Format 2...

Page 2: ...rint of U3 is compatible with many SO 8 package type reference devices so the user has the flexibility to select the reference supply to set the output range of the DAC8881 other than what is provided...

Page 3: ...ected Shorting pins 2 and 3 of both jumpers selects the reference voltages that are applied via J4 pins 18 and 20 respectively These voltages normally come from the host platform that is interfaced wi...

Page 4: ...should include adequate bypassing identifying and managing analog and digital signals and knowing or understanding the mechanical attributes of the components The critical part of the design is the la...

Page 5: ...s dimensions of 43 1800 mm 1 7000 inch 82 5500 mm 3 2500 inch and the board thickness is 1 5748 mm 0 062 inch Figure 2 through Figure 8 show the individual artwork layers Figure 2 Top Silkscreen Figur...

Page 6: ...www ti com Figure 4 Layer 2 Ground Plane Figure 5 Layer 3 Power Plane 6 DAC8881 Evaluation Module SLAU257A September 2008 Revised November 2009 Submit Documentation Feedback Copyright 2008 2009 Texas...

Page 7: ...rformance Figure 6 Layer 4 Bottom Signal Plane Figure 7 Bottom Silkscreen 7 SLAU257A September 2008 Revised November 2009 DAC8881 Evaluation Module Submit Documentation Feedback Copyright 2008 2009 Te...

Page 8: ...ware The EVM board is tested for all codes of 65535 and the device under test DUT is allowed to settle for 1ms before the meter is read This process is repeated for all codes to generate the measureme...

Page 9: ...6 10 F 1210 ceramic cap X7R 16V TDK C3225B63X7R1C106Z 4 7 C1 C2 C3 C4 C7 C15 C17 0 1 F 0805 ceramic cap X7R 50V 10 TDK C2012X7R1H104K 5 2 C9 C10 1 F 0805 ceramic cap X7R 16V 10 TDK C3216X7R1C105K 6 2...

Page 10: ...MMH 102 01 T T 28 10 Shunt 2mm shunt black Samtec 2SN BK G 29 0 R5 R7 R25 2 DNP 30 1 Shunt 0 100 shunt black Samtec SNT 100 BK T 1 P2 P4 and P6 parts are not shown in the schematic diagram All P desig...

Page 11: ...is connected to the noninverting input of the op amp U2 Figure 10 DAC8881 EVM Default Jumper Configuration 3 2 Host Processor Interface The host processor basically drives the DAC so the DACs proper...

Page 12: ...nd the signal used depends on the host controller that is selected to communicate with the DAC8881EVM Either signal can be chosen to drive the DAC8881 chip select CS pin The basic function of the CS a...

Page 13: ...the connector J4 The selected pins of the J4 connector as dictated by the jumper positions of the W2 and W7 jumpers can then be connected to the load to close the loop The EVM includes an external op...

Page 14: ...e loads Increasing the gain enhances the ability of the amplifier to drive even more capacitance and by adding a load resistor even improves the capacitive load drive capability Table 6 shows the jump...

Page 15: ...is is the default mode of the EVM from the factory Routes the reference feedback RFB pin of the DAC8881 to J4 pin 8 to provide the option to close the output op amp U2 loop as close as possible to the...

Page 16: ...wn status If jumper is installed on pins 13 and 14 the SDOSEL pin of the DAC8881 is tied to ground so that the DAC device can be operated in daisy chain mode DAC8881 IOVDD is powered with 5VD J3 DAC88...

Page 17: ...3 100 W12 W3 R1 0 CS VOUT1 VOUT2 TP5 IOVDD RFB RFB1 RFB2 W2 W7 Do not populate R5 R7 R25 W8 3 2 6 7 4 8 U5 OPA277 1 First Proto Release JLP J PARGUIAN 6489897 1 AVDD 5 VREFH 11 RFB 9 VOUT 8 CS 19 SCLK...

Page 18: ...O NOT connect the MMB0 to your PC before installing the DXP software as described in the DXP User s Guide Installing the software will ensure the necessary drivers are properly loaded to run the hardw...

Page 19: ...MMB0 Connect all other analog supplies as necessary to J14 on the MMB0 4 3 Software Running DXP Install DXP on a laptop or personal computer running Windows XP as per the detailed instruction in the...

Page 20: ...lease ensure no jumpers are placed on J1 pins 9 10 When the RST pin is low the device is in hardware reset mode and the input register and DAC latch are set to the value defined by the RSTSEL pin refe...

Page 21: ...1 2 routes the LDAC input to pin 15 of J2 This feature allows the user to Timer apply an LDAC input from an external source In this mode J2 pin 15 provides an interrupt to the DSP on the MMB0 which tr...

Page 22: ...terature Number DAC8881 SBAS422 REF02 SBVS003 REF5050 SBOS410 REF5045 SBOS410 OPA211 SBVS058 OPA627 SBOS165 OPA277 SBOS079 OPA2277 SBOS079 OPA227 SBOS110 5 2 Questions About This or Other Data Convert...

Page 23: ...oduct This notice contains important safety information about temperatures and voltages For additional information on TI s environmental and or safety programs please contact the TI application engine...

Page 24: ...ce TI is not responsible or liable for any such statements TI products are not authorized for use in safety critical applications such as life support where a failure of the TI product would reasonabl...

Page 25: ...Mouser Electronics Authorized Distributor Click to View Pricing Inventory Delivery Lifecycle Information Texas Instruments DAC8881EVM...

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