described above after 30s, remove the USB cable

from the board and reconnect it. Administrator priv-

ileges are required to install the USB device driver

on Windows.

10) Follow the directions of the Add New Hardware

Wizard to install the USB device driver. Choose the

Search for the best driver for your device option.

Specify the location of the device driver to be

C:\Program Files\MAX16825 (default installation

directory) using the Browse button. During device dri-

ver installation, Windows may show a warning mes-

sage indicating that the device driver Maxim uses does

not contain a digital signature. This is not an error con-

dition and it is safe to proceed with installation. Refer to

the TROUBLESHOOTING_USB.PDF document

included with the software for additional information.

11) Enable the power-supply output.

12) Start the EV kit software by opening its icon in the

Start | Programs menu. The MAX16825 EV kit soft-

ware main window appears, as shown in Figure 1.

13) Select the Output Enable checkbox and any of the

Channel_ checkboxes.

14) Verify that the corresponding attached LEDs are

illuminated.

Detailed Description of Software

Graphical User Interface

The main window’s GUI (Figure 1) is simple to use. A

mouse or the keyboard’s tab key is used to navigate

through the controls. The correct SPI write operation is

generated to update the internal registers of the

MAX16825 when any of these controls are used.

The software features a demo mode that is available by

selecting the View | Demo Mode menu item. When

operating in demo mode, all software communication to

the EV kit hardware is disabled and most of the soft-

ware’s GUI is functional. This feature enables the user

to evaluate the software without hardware connectivity.

The left-bottom status bar provides the USB-to-SPI

communication status. The right-bottom status bar pro-

vides the current program status. The MAX16825 EV kit

software configures the on-board SPI communication to

8kHz by default.

Software Startup

Upon starting the program, select the Output Enable

checkbox to enable the LED outputs. Deselecting the

Output Enable checkbox disables all three LED out-

puts. The Channel_ checkboxes enable and disable

individual channels.

General-Purpose 3-Wire (SPI) Interface Utility

The general-purpose 3-wire interface utility (Figure 2)

can also be used to communicate with the MAX16825

using low-level SPI commands. Select the Options |

Interface menu item and select the 3-wire interface tab

to access the utility. The utility configures the 3-wire ser-

ial-interface parameters, such as MSB position, CPOL,

CPHA, MOSI/MISO inverted logic, CS active state (high

or low), SPI clock (SCLK) speed, and custom selection

of SPI signal pins. The data to be sent is 8-bit data rep-

resented by a two-digit hexadecimal code. The code is

entered in the Data bytes to be written edit box and

transmitted by clicking on the Send Now button.

General Troubleshooting

Problem: Software reports it cannot find the inter-

face circuit.

• Is power LED D1 lit?

• Is the USB cable connected to the PC and EV kit?

• Is power applied to the VIN PCB pad?

• Has Windows plug-and-play detected the board?

Bring up the Control Panel > System > Device

Manager, and look at what device nodes are indi-

cated for USB. If there is an unknown device node

attached to the USB, delete it. This process forces

plug-and-play to try again.

MAX16825 Evaluation Kit

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3

Figure 1. MAX16825 Evaluation Kit Software—Graphical User

Interface (GUI)