EVAL-AD7718EB Analog Devices Inc, EVAL-AD7718EB Datasheet
EVAL-AD7718EB
Specifications of EVAL-AD7718EB
Related parts for EVAL-AD7718EB
EVAL-AD7718EB Summary of contents
Page 1
... AD7718 is available in the AD7718 datasheet available from Analog Devices and should be con- sulted in conjunction with this Technical Note when using the evaluation board. The evaluation board interfaces to the parallel port of an IBM compatible PC. Software is available with the Fig. 1. Evaluation Board Set-up REV ...
Page 2
... EVAL-AD7718-EB LINK AND SWITCH OPTIONS There are fifteen link options which must be set for the required operating setup before using the evaluation board. The functions of these link options are outlined below. Link No. Function LK1-LK8 These links are in series with the AIN1 through AIN8 analog inputs respectively. ...
Page 3
... J1 connector is shown in Fig. 3 and its pin designations are given in Table used to connect the evaluation board to the parallel (printer) port of a PC. Connection is via a standard printer cable used to connect the evaluation to any other system. The evaluation board should be powered up before a cable is connected to either of these connectors ...
Page 4
... Ground reference point for digital circuitry. Connects to the DGND plane on the evaluation board. 31- Connect. These pins are not connected on the evaluation board There are eighteen sockets relevant to the operation of the AD7718 on this evaluation board. The functions of these sockets are outlined in Table 4. Table 4. Socket Functions Socket Function J4 9-way D-Type connector used to interface to other systems ...
Page 5
... AD7718 can be operated with internal clock frequencies in the range 32.768 kHz +/- 10 There are two connectors on the AD7718 evaluation board as outlined in Table 5. Table 5. Connector Functions Connector Functions J3 PCB Mounting Terminal Block. The ...
Page 6
... EVAL-AD7718- There is one switch on the AD7718 Evaluation board. SW1 is a push-button reset switch. Pushing this switch activates the active low input on the AD7718 which resets the control logic, interface logic, calibration coefficients, digital filter and analog modulator of the part to power-on status. ...
Page 7
... Allows the user to write the current set of data to a file for later use - user needs to specify single or multi-channel data. About Provides information about the version of software being used. Multi-Channel Test Allows the user to display samples from selected channels at different update rates, polarities and ranges. Quit Ends the program EVAL-AD7718-EB Fig. 4. The Main Screen - 7 - Rev. B ...
Page 8
... EVAL-AD7718-EB The Program AD7718 Screen Fig. 5. shows the screen that appears when the Program AD7718 button is selected. This screen allows the user to select which register programmed. The Filter Register Screen Fig. 6. shows the Filter Register screen. When the screen is loaded the software will read the current contents from the Filter Register of the AD7718 and change the display accordingly ...
Page 9
... Offset Registers are read from the AD7718 and displayed. The user has the ability to change the values of either register if required. the default value for the Fullscale Cal Register is 535xx5 hex and the default value for the Zero Scale Cal Register is 800000 hex. EVAL-AD7718-EB Fig. 7. The Calibration Registers Screen - 9 - ...
Page 10
... EVAL-AD7718-EB The ADC Control Register Screen Fig. 8. shows the ADC Control Register Screen. This register controls Bipolar/Unipolar operation, Channel selection and Range selection for the Main ADC. When the screen is loaded the software reads the current contents from the ADC Control Register of the AD7718 and sets the buttons accordingly. Note if the Channel Configure bit is set in the Mode Register, the AD7718 channel configuration is changed - see AD7718 datasheets for more information ...
Page 11
... P1 & configured as inputs. Note pressing Update Display button will read the current contents of the I/ O Control Register and update the screen. Everytime a change is made, the software writes the new conditions to the AD7718 and then reads back from the I/O Control Register for conformation - ignoring databits P1DAT - P2DAT. Refer to AD7718 datasheets for more information. EVAL-AD7718- Rev. B ...
Page 12
... EVAL-AD7718-EB The Mode Register Screen The Mode Register Screen is shown in Fig. 10. When the screen is loaded the software reads the current contents from the Mode Register of the AD7718 and sets the buttons accordingly. This screen allows the user to change the operating mode of the AD7718, change the channel configuration, turn chopping on/off, select the reference voltage and power down the crystal oscillator ...
Page 13
... It is possible to add a delay to the read cycle by entering the required number of milliseconds between reading samples. It should be noted however that the accuracy of the time delay can be affected by other programs running under Windows, therefore this method is not suitable where equidistant sampling is required. EVAL-AD7718- Rev. B ...
Page 14
... EVAL-AD7718-EB The Noise Analysis Screen Once data has been read from the AD7718 ADC possible to perform some analysis on it. Fig. 13 shows the ADC Noise Analysis Screen. This screen displays the maximum and minimum codes read from the AD7718 ADC (in decimal and hexadecimal), as well as the average code, the average value and the RMS and Peak-Peak noise values. From this screen it is possible to display the data on a graph histogram of codes. Figures 14 & ...
Page 15
... EVAL-AD7718-EB Fig. 15. The Histogram Screen - 15 - Rev. B ...
Page 16
... EVAL-AD7718-EB The Multi-Channel Test Screen Fig. 16 shows the Multi-Channel Test Screen. This screen alows the user to select the channels for the multi- channel test. The user can specify range, update rate & polarity for the data. Note if the user selects an pseudo- differential channel, the respective fully-differential channel can't be used ...
Page 17
... Fig. 21. The Evaluation Board Schematic - 17 - EVAL-AD7718-EB Rev. B ...
Page 18
... EVAL-AD7718-EB Table 6. Component Listing and Manufacturers INTEGRATED CIRCUITS Component AD7718 AD780AN 74HC4050N 74C08SMD 74ACT244 SD103C Component 10µF ± 20% Tantalum (16 V) 0.1µF Ceramic (0805 SMD) RESISTORS Component Short Circuits 10k ±5% 0.25W Carbon Film R11-R13 3k ±5% 0.25W Carbon Film LINK OPTIONS ...
Page 19
... Low profile socket U2,U3,U6 CRYSTAL OSCILLATOR Component Location 32.768 kHz Oscillator Xtal 1 Fig. 22. The Evaluation Board Component Layout Diagram EVAL-AD7718-EB Harwin (32 pins needed) Farnell No. 519-959 Vendor FEC No. 221-533 - 19 - Rev. B ...
Page 20
... EVAL-AD7718-EB Fig. 23. The Evaluation Board Component Side Artwork Fig. 23. The Evaluation Board SolderSide Artwork - 20 - Rev. B ...