SNOU200 October   2024 LMH6518

 

  1.   1
  2.   Description
  3.   Get Started
  4.   Features
  5.   5
  6. 1Evaluation Module Overview
    1. 1.1 Introduction
    2. 1.2 Kit Contents
    3. 1.3 Specification
    4. 1.4 Device Information
  7. 2Hardware
    1. 2.1 Preliminary Setup
    2. 2.2 Basic Operation
    3. 2.3 Jumper Information
    4. 2.4 SPI
    5. 2.5 Logic Function Description
    6. 2.6 Header Information
  8. 3Hardware Design Files
    1. 3.1 Schematic
    2. 3.2 PCB Layouts
    3. 3.3 Bill of Materials (BOM)
  9. 4Additional Information
    1. 4.1 Trademarks

2.4 SPI

The following section highlights how to get data to and from the LMH6518EVM. A tip on how to confirm the USB2ANY is properly communicating with the LMH6518 is also given in this section.

Writing to the LMH6518:

To write to the LMH6518, the first bit sent (C7) must be 0. The serial interface protocol write operation is shown in Figure 2-11. The data that is read back in the Read data: text field in the USB2ANY GUI needs to be the same as the data written.

LMH6518EVM Serial Interface Protocol, Write OperationFigure 2-11 Serial Interface Protocol, Write Operation
LMH6518EVM Writing Data to LMH6518Figure 2-12 Writing Data to LMH6518
Note: A way to confirm that writing to the LMH6518 is working properly is to use bit D10 to switch between full power or auxiliary high impedance mode (Aux Hi-Z). When the device is set to Aux Hi-Z mode, the supply current of the device is reduced by about 60mA. Writing 00 04 00 to the device switches the device to Aux Hi-Z mode, and can be switched back again to full power using 00 00 00.

Reading from the LMH6518:

To read from the device, the first bit sent to the device (C7) must be 1. The serial interface protocol read operation is shown in Figure 2-13. After writing a recognizable configuration to the device, such as 00 00 EF, the device configuration can be read by writing 80 00 00 as 8 sets the very first bit (C7) to 1. The data read back for this specific configuration will be 80 00 EF as shown in Figure 2-14 and Figure 2-15.

LMH6518EVM Serial Interface Protocol, Read OperationFigure 2-13 Serial Interface Protocol, Read Operation
LMH6518EVM Writing Recognizable Configuration to LMH6518Figure 2-14 Writing Recognizable Configuration to LMH6518
LMH6518EVM Reading Recognizable Configuration to LMH6518Figure 2-15 Reading Recognizable Configuration to LMH6518
Note: When initially writing to the LMH6518, if the data immediately read back is not the same as the data that is written there can be a delay. To fix this, lower the bit rate in the configuration panel found in the SPI tab. When reading from the LMH6518, if the read data is not the expected configuration, this can also be corrected by adjusting the bit rate.