Texas Instruments BUF08821EVM User manual

User's GuideSBOU066 – September 2008
BUF08821EVM Evaluation Board and Software Tutorial
This user's guide describes the characteristics, operation, and use of the BUF08821EVM evaluationboard. It discusses how to set up and configure the software and hardware, and reviews various aspectsof the program operation. Throughout this document, the terms evaluation board,evaluation module, andEVM are synonymous with the BUF08821EVM. This user's guide also includes information regardingoperating procedures and input/output connections, an electrical schematic, PCB layout drawings, and aparts list for the EVM.
Contents1 Overview ...................................................................................................................... 22 Unpacking the EVM ......................................................................................................... 23 BUF08821EVM Software ................................................................................................... 24 EVM Operation ............................................................................................................... 55 Using the BUF08821EVM Software ....................................................................................... 86 Hardware and Schematic ................................................................................................. 18
List of Figures
1 BUF08821EVM Software Installation ..................................................................................... 32 COM Port Selection and Dialog Window ................................................................................. 33 BUF08821EVM Software About Button ................................................................................... 44 BUF08821EVM Switch and Jumper Locations .......................................................................... 55 BKSEL Switch ................................................................................................................ 66 BUF08821EVM Jumper JP1 Set for Logic '1' ............................................................................ 67 BUF08821EVM Jumper JP1 Set for Logic '0' ............................................................................ 68 BUF08821EVM Jumper JP2 Set for BKSEL Switching ................................................................. 79 BUF08821EVM Jumper JP2 Set for External Signal Switching ....................................................... 710 BUF08821EVM Software GUI ............................................................................................. 811 Power Supply Measurement and Recording ............................................................................. 912 Reset and Read DAC Buttons ............................................................................................ 1013 Save to File Dialog Box ................................................................................................... 1114 Working with a Saved BUF08821 Data File ............................................................................ 1215 Load From File Button ..................................................................................................... 1316 Changing the DAC Analog Voltage ...................................................................................... 1417 Run Batch Dialog Box ..................................................................................................... 1518 Control Panel Button and Graphical Sliders ............................................................................ 1619 Program OTP All Channels Button ...................................................................................... 1720 Program OTP Out Button and Write OTP Reg Dialog ................................................................ 1721 Max Bank Field ............................................................................................................ 1822 BUF08821EVM Schematic ................................................................................................ 1923 BUF08821EVM PCB Top Layer (Component Side) ................................................................... 2024 BUF08821EVM PCB Bottom Layer (Solder Side) ..................................................................... 21
Pentium is a registered trademark of Intel Corporation.Microsoft, Windows are registered trademarks of Microsoft Corporation.I
2
C is a trademark of NXP Semiconductors, Inc.All other trademarks are the property of their respective owners.
SBOU066 – September 2008 BUF08821EVM Evaluation Board and Software Tutorial 1Submit Documentation Feedback

1 Overview
2 Unpacking the EVM
3 BUF08821EVM Software
3.1 Hardware Requirements
Overview www.ti.com
The BUF08821 is a programmable gamma-voltage generator and V
COM
calibrator with integrated two-bankmemory. This device offers 8 programmable gamma channels and one programmable V
COM
channel. TheBUF08821EVM is a platform for evaluating the performance of the BUF08821 under various signal,reference, and supply conditions.
This document gives a general overview of the BUF08821EVM, and provides a general description of thefeatures and functions to be considered while using this evaluation module.
Upon opening the BUF08821EVM kit, please check to make sure that the following items are included:•One BUF08821EVM printed circuit board (PCB);•One serial connection cable with RS-232/RJ-45 plug connector; (RS-232 and RJ-45 connectors)•One CD containing the BUF08821EVM software, and electronic copies of the BUF08821 product datasheet and this user's guide ;
If any of these items are missing, please contact the Texas Instruments Product Information Centernearest you to inquire about a replacement.
The minimum hardware requirements for the BUF08821EVM sofware are:•IBM PC-compatible computer with a Microsoft
®
Windows
®
98/ME/NT/2000/XP operating system•Pentium
®
or equivalent processor•64MB of RAM•Hard disk drive with at least 100MB free space•Available COM port•Mouse
•VGA adapter card and monitor
2BUF08821EVM Evaluation Board and Software Tutorial SBOU066 – September 2008Submit Documentation Feedback

3.2 Installation
3.3 Software Description and Set-Up
www.ti.com BUF08821EVM Software
The BUF08821EVM software is included on the CD that is shipped with the EVM. It is also availablethrough the BUF08821EVM product folder on the TI web site at www.ti.com . To download the software toyour system, insert the disc into an an available CD-ROM drive. Navigate to the drive contents and openthe BUF08821EVM software folder. Locate the compressed file ( BUF08821EVM.zip) and open it. Extractthe BUF08821EVM files into a specific BUF08821 folder on your hard drive.
Once the files are unzipped, navigate to the BUF08821 folder that you created on your hard drive. Locatethe setup.exe file; click the file to start the installation process, as shown in Figure 1 .
Figure 1. BUF08821EVM Software Installation
Follow all on-screen commands to finish installing the software.
The EVM software is controlled through a graphical user interface (GUI). The software communicates withthe EVM through an available COM or other serial port on the PC. Pressing the COM Setting buttonbrings up a panel that allows you to change the serial port number through which the PC communicateswith the BUF08821EVM, as shown in Figure 2 . COM1 is an appropriate choice for most PCs. You canalso set the appropriate baud rate through the same dialog box.
Figure 2. COM Port Selection and Dialog Window
SBOU066 – September 2008 BUF08821EVM Evaluation Board and Software Tutorial 3Submit Documentation Feedback

BUF08821EVM Software www.ti.com
The BUF08821EVM software allows the user to read and write to all registers in the BUF08821 gammacorrection buffer. Furthermore, it allows programming of the OTP register on the BUF08821. The softwarealso permits the user to select either I
2
C™ address.
Press the About button as shown in Figure 3 to verify that you have the latest version of the software.
Figure 3. BUF08821EVM Software About Button
4BUF08821EVM Evaluation Board and Software Tutorial SBOU066 – September 2008Submit Documentation Feedback

4 EVM Operation
www.ti.com EVM Operation
Figure 4 shows the BUF08821EVM with the test point, switch, and jumper locations noted.
Figure 4. BUF08821EVM Switch and Jumper Locations
SBOU066 – September 2008 BUF08821EVM Evaluation Board and Software Tutorial 5Submit Documentation Feedback

4.1 BKSEL
Bank 1
Bank 2
BKSEL
4.2 JP1
Set for Logic ‘1’ Software set for A0 = 1
Set for Logic ‘0’ Software set for A0 = 0
EVM Operation www.ti.com
The BKSEL switch (illustrated in Figure 5 ) selects the memory bank to be used when operating the EVM.Bank 1 selects the gamma curve that is stored in Bank_0 of the BUF08821. Bank 2 selects the gammacurve that is stored in Bank_1 of the BUF08821.
The SCL and SDA jumpers must be installed on the EVM in order to allow communication between theboard and the BUF08821. The communications cable must be connected to COM1 or another COM porton your PC.
Figure 5. BKSEL Switch
Jumper JP1 is used to set the I
2
C address pin of the BUF08821 to logic high or logic low. When J1 is inthe position shown in Figure 6 , A0 on the BUF08821 is connected to DV
DD
(logic '1'). Note that thesoftware Change Address button must be as shown in Figure 6 for A0 = '1'.
Figure 6. BUF08821EVM Jumper JP1 Set for Logic '1'
When JP1 is in the position shown in Figure 7 , A0 on the BUF08821 is connected to GND (logic '0'). Notethat the software must be as shown in Figure 7 for an address of A0 = '0'.
Figure 7. BUF08821EVM Jumper JP1 Set for Logic '0'
Note: Pressing the Change Address button (located near the top of the interface) changes the I
2
Caddress that the software writes to. In Figure 7 , the address is A0 = '0'. Pressing the buttonchanges it to A0 = '1', as shown in Figure 6 . Note that the Change Address button iscolor-coded to help you quickly identify the current address. Red indicates that the address isA0 = '0'.
BUF08821EVM Evaluation Board and Software Tutorial6 SBOU066 – September 2008Submit Documentation Feedback

4.3 JP2
JP2 selects either BKSEL
or an external signal
In this position, BKSEL
is used to switch
between memory banks
Int
Ext
JP2
BKSEL
JP2 selects either BKSEL
or an external signal
In this position, memory banks
switched according to
external signal
applied via connector
Int
Ext
JP2
BKSEL
www.ti.com EVM Operation
Jumper JP2 selects either the BKSEL switch on the EVM or an external signal to switch between the twononvolatile memory banks of the BUF08821. When JP2 is in the position shown in Figure 8 , the BKSELswitch is used to switch between the memory banks.
Figure 8. BUF08821EVM Jumper JP2 Set for BKSEL Switching
When JP2 is in the position shown in Figure 9 , the memory banks are switched according to the externalsignal applied via the connector.
Figure 9. BUF08821EVM Jumper JP2 Set for External Signal Switching
SBOU066 – September 2008 BUF08821EVM Evaluation Board and Software Tutorial 7Submit Documentation Feedback

5 Using the BUF08821EVM Software
Using the BUF08821EVM Software www.ti.com
Figure 10 shows the EVM software interface.
Figure 10. BUF08821EVM Software GUI
8BUF08821EVM Evaluation Board and Software Tutorial SBOU066 – September 2008Submit Documentation Feedback

5.1 Change Address Button
5.2 Measuring the Power Supply
Measure the power-supply value
(V ) against GND, and
enter it here
S
The voltage out of each DAC
will be calculated according to
the V value entered.
S
Changing this cell immediately changes
the output of DAC8 to 0.996V.
www.ti.com Using the BUF08821EVM Software
The interface displays the last power-supply value used for the new address. This feature is helpful whenchanging back to an address that was previously used. Whenever the address is changed, a Read DACcommand is automatically performed so that all the DAC output displays are updated. Red indicates thatthe address is A0 = '0', as Figure 10 shows.
You must measure the power supply (V
S
) value against GND, and then enter it in the Vsup field of thesoftware interface, as shown in Figure 11 . The voltage out of each DAC is calculated according to the V
Svalue entered.
Figure 11. Power Supply Measurement and Recording
Measure V
S
at the location indicated in Figure 4 .
SBOU066 – September 2008 BUF08821EVM Evaluation Board and Software Tutorial 9Submit Documentation Feedback

V = V Code_in_decimal´
DAC_CHANNEL S
1024
(1)
V = 15V 68 / 1024 = 0.996V´
DAC_CHANNEL
5.3 Reset and Read DAC Buttons
5.4 Save to File
Using the BUF08821EVM Software www.ti.com
For example, changing the value in the DAC 15 cell immediately changes the output of DAC15 to 0.996V.The calculation is performed according to Equation 1 .
For example:
DAC 15: Code 44 (hexadecimal) = 68 (decimal)
Push the ReadDAC button to read the binary value in the DAC output registers of the BUF08821. Pushingthe Reset button forces an I
2
C general call reset and causes all registers in the BUF08821 to reset to therespective default values (mid-code or V
S
/2). Figure 12 illustrates the Reset and Read DAC buttons.
Figure 12. Reset and Read DAC Buttons
The register configurations of the BUF08821 DACs are displayed in both analog voltage and inhexadecimal (see Figure 11 ). The DAC codes (that is, gamma voltages) can be saved into a text file usingthe Save to File button.
BUF08821EVM Evaluation Board and Software Tutorial10 SBOU066 – September 2008Submit Documentation Feedback