Demonstration circuit 458 is configured to be a part of the LTC QuickEval™ system for quick and easy I²C™ control. The QuickEval software is downloaded from the Linear Technology website. After installing the software, it is always best to run the update periodically. Connect the USB controller board, DC590A, to a computer and open the QuickEval software as shown in Figure 2. Through a 14-pin ribbon cable connect the DC458 to the controller board and the LTC4240 interface software will be brought up. Refer to Figure 3 for the following interface . 1. An I²C address byte needs to be selected to match that of the LTC4240 so the host can communicate with it. Select a Write Address from the list or simply click on Find Address to cycle through the possible addresses for the LTC4240 and show which addresses responded with an acknowledge. If no address is found, the selected address will be set 00h. Check the connections and setup and try again. 2. The Command Byte field on the QuickEval Interface menu is the write register of the LTC4240. To set a bit to 1, select the appropriate box. For example, selecting C5 will only send data byte 20h. Then checking C4 will send data byte 30h. Unchecking C5 will send data byte 10h. 3. The Status field displays the read register of the LTC4240. Click on Single Refresh to do a single read from the LTC4240, or check Continuous Read to poll the LTC4240 and uncheck to halt the poll. The poll is set to read every 500ms. 4. The Quick Read field shows the status of the Red Fault# LED and Green HEALTHY# LED. The Expansion Configuration is given by PRSNT1,2# bits. The FAULTCODE0,1 bits encode which supply has caused a fault. Note: If the DC458 is disconnected or a communications error has occurred, the LTC4240 software will close and return to main QuickEval software.