SBAU269C October   2016  – August 2021 ADS8900B

 

  1.   Trademarks
  2. 1EVM Overview
    1. 1.1 ADS8900EVM-PDK Kit Features
    2. 1.2 ADS8900EVM Features
  3. 2Analog Interface
    1. 2.1 ADS8900B Connections and Decoupling
    2. 2.2 ADC Amplifier Input Drive
    3. 2.3 Voltage Reference and VCM Scaling
  4. 3Digital Interface
    1. 3.1 multiSPI™ for ADC Digital I/O
    2. 3.2 I2C Bus for Onboard EEPROM
  5. 4Power Supplies
    1. 4.1 Positive Supply and Test Points
    2. 4.2 Negative Supply
  6. 5ADS8900EVM-PDK Initial Setup
    1. 5.1 Software Installation
    2. 5.2 Default Jumper Settings for Differential Inputs
    3. 5.3 Default Jumpers for Bipolar, Single-Ended Inputs
    4. 5.4 Default Jumpers for Unipolar, Single-Ended Inputs
    5. 5.5 External Source Requirements for ADS8900 Evaluation
  7. 6ADS8900EVM-PDK Operation
    1. 6.1 EVM GUI Global Settings for ADC Control
    2. 6.2 Register Map Configuration Tool
    3. 6.3 Time Domain Display Tool
    4. 6.4 Spectral Analysis Tool
    5. 6.5 Histogram Tool
    6. 6.6 Linearity Analysis Tool
    7. 6.7 ADS8900BEVM Support for ADS8910B and ADS8920B Devices
  8. 7Bill of Materials, PCB Layout, and Schematics
    1. 7.1 Bill of Materials (BOM)
    2. 7.2 PCB Layout
    3. 7.3 Schematics
  9. 8Revision History

6.1 EVM GUI Global Settings for ADC Control

Although the EVM GUI does not allow direct access to the levels and timing configuration of the ADC digital interface, the EVM GUI does give users high-level control over virtually all functions of the ADS8900, including interface modes, sampling rate, and number of samples to be captured.

Figure 6-3 identifies the input parameters of the GUI (as well as their default values) through which the various functions of the ADS8900 can be exercised. These are global settings as they persist across the GUI tools listed in the top left pane (or from one page to another).

Figure 6-3 EVM GUI Global Input Parameters

The interface configuration options in this pane allow the user to choose from various SPI and multiSPI host interface options available on the ADS8900B. The host always communicates with the ADS8900B using the standard SPI protocol over the single SDI lane, irrespective of the mode selected for data capture.

The drop-down boxes under the interface configuration sub-menu allows the user to select the data capture mode. The SDO Mode drop-down allows selection between single-, dual- and quad-SDO lanes; Data Read between source and system synchronous modes and Output Data Rate between SDR and DDR modes. Detailed descriptions of each of these modes is available in the ADS8900 data sheet.

The user may select SCLK Frequency and Sampling Rate on this pane, which are dependent on the device mode selected. The GUI allows the user to enter the targeted values for these two parameters and the GUI computes the best values that can be achieved, considering the timing constraints of the selected device mode.

The user may specify a target SCLK frequency (in hertz) and the GUI matches this value as closely as possible by changing the PHI PLL settings and the achievable frequency that may differ from the target value displayed. Similarly, the sampling rate of the ADC can be adjusted by modifying the target Sampling Rate argument (also in hertz). The achievable ADC sampling rate may differ from the target value, depending on the applied SCLK frequency and the selected device mode, with the closest match achievable displayed thereafter.

The final option in this pane is the selection for the Update Mode. The default value is Immediate, which indicates that the interface settings selection made by the user is applied to configure both the host and the ADS8900 instantly. Manual indicates that the selection made is applied only when the user finalizes their choices and is ready to configure the device. This process is described in more detail in Section 6.2.