Texas Instruments TLC5944EVM-358 User manual

User's GuideSLVU306 – April 2009
TLC5944EVM-358
This user’s guide describes the characteristics, setup, and use of the TLC5944EVM-358 EvaluationModule (EVM). This EVM helps the user evaluate the features of the Texas Instruments TLC5944, whichis a 16-channel, constant-current LED driver. This user’s guide includes setup instructions, a schematicdiagram, a bill of materials, printed-circuit board layout drawings, and software instructions.
Contents1 Introduction ................................................................................................................... 21.1 Requirements ....................................................................................................... 21.2 Related Documentation From Texas Instruments .............................................................. 32 Setup .......................................................................................................................... 32.1 Input/Output Connector Descriptions............................................................................. 42.2 Software Setup ...................................................................................................... 62.3 Hardware Setup ..................................................................................................... 63 Operation ..................................................................................................................... 73.1 Running the Software .............................................................................................. 73.2 Software Features .................................................................................................. 73.3 Hardware Features ................................................................................................ 114 Schematics, Board Layouts, and Bill of Materials ...................................................................... 124.1 Schematics ......................................................................................................... 124.2 Board Layouts ..................................................................................................... 194.3 Bill of Materials .................................................................................................... 28
List of Figures
1 Board Connections .......................................................................................................... 32 TLC5944EVM Software Start-Up Screen ................................................................................. 73 TLC5944EVM Software with Ghosting Demo Enabled. ................................................................ 94 Information Bar ............................................................................................................. 105 HPA357A - Schematic 1 .................................................................................................. 126 HPA357A - Schematic 2 .................................................................................................. 137 HPA358A Schematic 1 .................................................................................................... 148 HPA358A Schematic 2 .................................................................................................... 159 HPA358A Schematic 3 .................................................................................................... 1610 HPA358A Schematic 4 .................................................................................................... 1711 HPA358A Schematic 5 .................................................................................................... 1812 HPA357A Assembly Layer Routing ...................................................................................... 1913 HPA357A Top Layer Routing ............................................................................................ 2014 HPA357A Layer 2 Routing ................................................................................................ 2115 HPA357A Layer 3 Routing ................................................................................................ 2216 HPA357A Bottom Layer Routing ......................................................................................... 2317 HPA358A Assembly Layer ............................................................................................... 2418 HPA358A Top Layer ...................................................................................................... 2519 HPA358A Layer 2 ......................................................................................................... 2620 HPA358A Layer 3 .......................................................................................................... 2721 HPA358A Bottom Layer Routing ......................................................................................... 28
List of Tables
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1 Introduction
1.1 Requirements
1.1.1 Software
1.1.2 Host Computer
1.1.3 Power Supply Requirements
Introduction www.ti.com
1 Available Settings .......................................................................................................... 112 HPA357A Bill of Materials ................................................................................................. 283 HPA358A Bill of Materials ................................................................................................. 29
The Texas Instruments TLC5944 is a 16-channel, constant-current LED driver that is capable of driving upto 60 mA per channel. The TLC5944 has several features including 6-bit Dot Correction, 12-bit grayscalePWM dimming, Pre-Charge FET, LED failure and overtemperature detection. For more information onPWM dimming, see the TLC5944 data sheet (SBVS112 ), a Dot Correction technical paper (SLYT225 ),and a PWM Dimming technical paper (SLYT238 ) on the TI Web site. This EVM contains three TLC5944integrated circuits (IC) connected in series. The three ICs drive 16 light-emitting diodes (LED), eachhaving a red, green, and blue LED in the same package.
Multiplexing, Ghosting, and Pre-Charge FETs
The EVM is also configured to demonstrate LED multiplexing, which is connecting more than one LED toan LED driver output. The EVM demonstrates multiplexing by connecting an additional row of red LEDs toone of the LED driver ICs. The practice of multiplexing LEDs often generates a phenomenon known asGhosting. This phenomenon is also called Phantom Noise or Spike Noise. Ghosting occurs when an LEDis programmed to be off, but is visually illuminated. The LED is illuminated because of stray currentsflowing through it that are generated by switching the rows of LEDs in and out of the circuit, stray boardcapacitance, and mismatches in diode forward voltages. The TLC5944 contains Pre-Charge FETs thatshunt these currents around the LEDs so they do not produce light. The EVM GUI software allows theuser to easily demonstrate multiplexing both with and without the Pre-Charge FETs to see the ghostingeffect.
In order to operate this EVM, the following components must be connected and properly configured. Allcomponents, software, and connectors are supplied in the EVM except for the host computer and the dcpower supply
Texas Instruments provides a compact disk (CD) in the EVM kit that contains the software necessary toevaluate the TLC5944EVM. Check the TLC5944 product folder on the TI Web site (www.ti.com ) forupdates to the software.
A computer with a USB port is required to operate this EVM. The TLC5944 software runs on the personalcomputer (PC) and communicates with the EVM via the PC’s USB port.
PC Requirements:
•Windows™ 2000 or Windows XP operating system•USB port•Minimum of 30 MB of free hard disk space (100 MB recommended)•Minimum of 256 MB of RAM
A dc power supply capable of delivering 5 V at 1 A is required to power the EVM.
controlCARD is a trademark of Texas Instruments.Windows, Internet Explorer are trademarks of Microsoft Corporation.VeriSign is a trademark of VeriSign, Inc.ZigBee is a trademark of ZigBee Alliance.
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1.1.4 Printed-Circuit Board Assemblies
TUSB3410 TRS3221
TRS3221 F2808
TLC5944
USB
DSP Board (TMS320F2808)
LED Driver Board (HPA358)
LED Board
(LEDEVM-357)
8
16
16
16
GPIOs
UART
RS -232
UART
Host Computer
TLC5944
TLC5944
1.2 Related Documentation From Texas Instruments
2 Setup
www.ti.com Setup
The TLC5944EVM-358 EVM kit contains three printed-circuit boards: HPA358 (Driver board), HPA357(LED board), and TMDSCNCD2808 (DSP board).
Driver Board: The Driver board contains the TLC5944 ICs and their required external components. Thisboard contains several jumpers and connectors that enable you to customize the board for specificoperating conditions. This board interfaces directly to the host computer via a USB connector. The EVMGUI software communicates with the Driver board through a TUSB3410. The TUSB3410 communicateswith the DSP board with an RS-232 protocol. The Driver board contains resistors R16-R27 that set abinary code to tell the DSP what EVM is connected. It contains all power supply circuitry as well ascircuitry containing Q1 and Q2 to enable and disable the ghosting features of the IC. The Driver board isdesigned to directly drive the LED board; however, the customer may also remove the LED board to drivea custom LED board.
LED Board: The LED board contains two rows of LEDs. Row A consists of 16 LEDs, each with threeindividual LEDs in the same package: a red, a green, and a blue LED. Row B consists of a 16 LEDs, eachwith a single red LED. It also contains the circuitry required to multiplex between Row A and Row B. Adigital signal, ROW_CTRL_0, from the Driver board connects power to Row A when high and connectspower to Row B when low. The orderable Texas Instruments part number for this PCB is LEDEVM-357.
DSP Board: The DSP board contains a TMS320F2808 ('F2808) microcontroller that programs andcontrols the three TLC5944 ICs on the Driver board. The 'F2808 DSP decodes the information it receivesfrom the LED Driver board and converts it into a form required by the TLC5944 ICs. The DSP board’sorderable part number is TMDSCNCD2808. Figure 1 shows how these boards are connected.
Figure 1. Board Connections
1. TLC5944, 16-Channel, 12-Bit PWM LED Driver With 6-Bit Dot Correction and Pre-Charge FET datasheet (SBVS112 )2. TLC5944 software (SLVC186 )3. TMDSCNCD2808 DSP controlCARD™ documents (SPRR101 )
This section describes the jumpers and connectors on the EVM as well as how to properly connect, setup, and use the TLC5944EVM-358.
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2.1 Input/Output Connector Descriptions
2.1.1 J1 – USB Input Connector
2.1.2 J2 – ZigBee™ Input Connector
2.1.3 J3 – RS-232 Input Connector
2.1.4 J4 – DSP Board Connector
2.1.5 J5 – JTAG Input Connector
2.1.6 J6 – VIN
2.1.7 J7 – GND Connector
2.1.8 J8 – Input Power Connector
Setup www.ti.com
This mini-USB connector connects the EVM directly to the host PC’s USB port.
This connector mates to the HPA358 LED board. The customer also can connect a custom board to thisconnector with a 30-pin ribbon cable. To minimize stray inductance and ringing on the output traces, makeconnections to this connector as short as possible. This connector allows the user to connect ZigBeedevices such as the eZ430-RF2500. The user can write customized code to control the TLC5944EVM witha wireless ZigBee connection. J2 is not populated or used with the supplied EVM software.
This connector allows the user to connect an RS-232 device. The user can write customized code tocontrol the TLC5944EVM or to modify the DSP board’s firmware. J3 is not populated or used with thesupplied EVM software.
The DSP board plugs into the J4 connector on the Driver board.
This connector can be used for JTAG communications to help debug user-generated software. J5 is notpopulated or used with the supplied EVM software.
This is the positive input supply to the EVM. The input voltage must be between 5 V and 15 V for normaloperation with no multiplexing. When Row A and Row B are multiplexed by checking the Ghosting Demobutton in the software, the maximum operating voltage is 10 V. The 10-V maximum voltage is limited byswitching losses in the FETs on the LED board. The EVM can be operated with 15 V when multiplexing, ifforced air cooling is used on the LED board. To minimize power dissipation, the input voltage must be aslow as possible. The leads to the input supply must be twisted and kept as short as possible to minimizeEMI transmission.
This connector is the return for the input supply to the EVM. The leads to the input supply must be twistedand kept as short as possible to minimize EMI transmission.
This is a right-angle miniature power jack with a 3,5-mm diameter connection. The user can use thisconnector to supply input power to the EVM from an ac-to-dc plug-in adapter. The inner pin on theconnector is connected directly to J6 (Vin). The outer pin on the connector is connected directly to J8(GND). When using an ac-to-dc plug-in adapter, ensure that the plug-in adapter’s output voltage is stableand does not drop below 5 V when loaded.
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2.1.9 J9 – Communications Connector
2.1.10 J10 – LED Connector
2.1.11 J11 – LED Connector
2.1.12 JP1 – Default 'F2808 Boot Location
2.1.13 JP2 – Red LED
2.1.14 JP3 – Green LED
2.1.15 JP4 – Blue LED
2.1.16 JP5 – SCL
www.ti.com Setup
This connector contains shorting shunts that connect the 'F2808 DSP to the TLC5944 LED drivers. Theshunts are preconfigured to properly connect the DSP’s GPIO control signals to the LED driver ICs. TheGND pins on this connector do not need shorting shunts because these pins are connected to the groundplane of the PCB. The user can remove all shorting shunts to disconnect the 'F2808 from the TLC5944ICs. This allows the user to connect control signals from a separate microprocessor to this connector toprogram the LED drivers. The XERR signal does not need a shorting jumper because the user graphicalinterface (GUI) software does not use this signal.
CAUTION
Do not drive the outputs of the TMS320F2808 on the DSP board with externalcontrol signals.
This connector mates to the HPA358 LED board. The user also can connect a custom board to thisconnector with a standard 30-pin ribbon cable with 0.1-inch pin-to-pin spacing. In order to minimize strayinductance and ringing on the output traces, connections to this connector must be as short as possible.
This connector mates to the HPA358 LED board. The user also can connect a custom board to thisconnector with a standard 30-pin ribbon cable with 0.1-inch pin-to-pin spacing. In order to minimize strayinductance and ringing on the output traces, connections to this connector must be as short as possible.
When a short is connected between pins 1-2, the 'F2808 boots up from the USB port connector, J1. Whena short is connected between pins 2-3, the 'F2808 boots up from its internal flash EEPROM. The defaultboot location is the 'F2808 internal EEPROM. Firmware updates to the EEPROM require changes to theJP1 settings. The GUI software provides detailed instructions on how to update the firmware. If the userconfigures the EVM to communicate through the RS-232 or Zigbee connector, short JP1 pins 1 and 2together so that the DSP boots from the RS-232 or Zigbee connector.
This jumper must be shorted to connect the red LED driver’s OUT15 pin to the red LED. This jumper canbe opened to measure the current flowing into the OUT15 pin from the red LED.
This jumper must be shorted to connect the green LED driver’s OUT15 pin to the green LED. This jumpercan be opened to measure the current flowing into the OUT15 pin from the green LED.
This jumper must be shorted to connect the blue LED driver’s OUT15 pin to the blue LED. This jumpercan be opened to measure the current flowing into the OUT15 pin from the blue LED.
This jumper is used to program the EEPROM, U1, at assembly. This jumper must be shorted to connectthe TUSB3410 to the EEPROM for normal operation.
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2.1.17 JP6 – SDA
2.1.18 S1 – Power Switch
2.2 Software Setup
2.3 Hardware Setup
Setup www.ti.com
This jumper is used to program the EEPROM, U1, at assembly. This jumper must be shorted to connectthe TUSB3410 to the EEPROM for normal operation.
This switch connects and disconnects input power from the EVM.
If installing from a CD, insert the CD and run Setup.exe. Follow all the prompts to allow the software to beinstalled.
If installing from the TI Web site, go to the URL www.ti.com
Note: This installation page is best viewed with Microsoft Internet Explorer™ browser. It may notwork correctly with other browsers.
Click on the install button; your PC gives you a security warning and asks if you want to install thisapplication. Select Install to proceed.
With both types of installation, the software attempts to install the Microsoft Dot Net Framework 2.0 (if it isnot already installed). This framework is required for the software to run.
After installation, the software automatically runs.
During future use of the software, it may prompt you to install a new version if it becomes available on theweb.
Note: VeriSign™ code signing is used to prevent any malicious code from changing thisapplication. If at any time in the future the binaries are modified, the code no longer attemptsto run.
Ensure that S1 is in the OFF position.
Ensure that the shorting shunt is installed on JP1. The default for normal EVM operation is to short pins 2and 3 together.
Ensure that the shorting shunts are installed on JP2, JP3, JP4, JP5, and JP6.
Connect the LED board (HPA358) to the LED Driver board (HPA274).
Connect the DSP board (TMDSCNCD2808) to the LED Driver board (HPA274). Ensure the DSP board isfully seated in J4 with the tabs positioned to lock the DSP board in place.
Connect the LED Driver board to the host computer using the supplied USB cable.
Using either the J6 and J7 input power connectors or the J8 power jack connector, connect an inputvoltage supply to the TLC5944EVM board. The TLC5944 requires an input voltage between 5 V and 10 V.The input supply must be capable of supplying at least 1.5 A. Note that some ac-to-dc plug-in adapters donot provide clean power. Ensure that the input voltage is well regulated to avoid intermittentcommunication problems.
CAUTION
Hot plugging the input supply with long leads can generate transients on theinput supply bus that exceed the maximum ratings of the EVM. The inputsupply must be connected before it is turned on.
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3 Operation
3.1 Running the Software
3.2 Software Features
www.ti.com Operation
Turn on the input supply voltage.
Move S1 from OFF to ON.
The 16 LEDs now are displaying a default pattern.
This section provides instructions on how to turn on the TLC5944EVM and operate the software.
The user now can run the host computer software and change the LED programming with the easy-to-usegraphical interface.
Click on the TLC594x EVM GUI icon on the host computer to start the software. If no icon appears on thehost computer, then use the start button in the lower left corner of the screen to browse the programfolders to find the software. The default directory for software installation is Program Files\TexasInstruments\TLC594x EVM GUI Application. The executable file name is TLC594x.exe. Once started, thesoftware checks the firmware in the DSP board to ensure it is compatible with the software. If the firmwareis not compatible, the software gives the user instructions on how to reprogram it. Once the software isstarted and communication is established between the GUI and the EVM, the user can use the graphicalinterface to program the LEDs. If the EVM is properly connected, the software screen looks like Figure 2when first opened.
Figure 2. TLC5944EVM Software Start-Up Screen
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3.2.1 Color Picker
3.2.2 Patterns
3.2.3 Dot Correction
3.2.4 Timing Control
3.2.5 Anti-Ghosting
Operation www.ti.com
This window allows the user to choose the red, green, and blue PWM value for each LED. The softwareprovides three options for choosing an LED’s color. The user can manually enter the PWM values into thethree text boxes, use the mouse to pick colors from the color bars, or use the mouse to click on a colorfrom the custom color pallet. The color chosen in the Color Picker window is immediately displayed in theLEDs that are highlighted in the LED Frames window. The user can add custom colors to the pallet bydragging the current color to the custom color pallet. Custom colors can be deleted by right-clicking on thecolor to be removed. The TLC5944 is capable of displaying the full 2
12
, or 4096 brightness levels per LED.
This window provides the user with several preprogrammed LED frame patterns. Choosing a patternimmediately programs the LED Frames window with the pattern and then displays the pattern with theLEDs.
These two windows allow the user to individually control the EVM’s red, green, and blue dot correctionvalues. Each LED’s Dot Correction value can be individually programmed. Dot Correction data is onlywritten to the EVM when one of the three values change. To change an LED’s dot correction value, selectindividual LEDs by clicking on each LED or select all LEDs by checking the box to the left of the LEDs.Then adjust the Dot Correction value. The programmed Dot Correction value is used for all frames. DotCorrection values can not be changed from frame to frame.
The options in this window allow the user to modify the timing parameters of the signals written to theTLC5944 ICs. Note that all times and frequencies are approximate.
Clock: This drop-down menu allows the user to select the EVM’s serial clock (SCLK) and grayscale(GSCLK) frequencies. The available clock frequencies are integral divisions of the 'F2808 clock frequencyand cannot be modified.
Frame Rate: This shows the refresh rate for a single frame update. The Frame Rate is approximately1/period, where period is the time to display all 2
12
grayscale pulses at the chosen clock frequency plusthe time the BLANK signal is high.
BLANK Width: This adjusts the width of the BLANK pulse.
XLAT Width: This adjusts the width of the XLAT pulse.
XLAT Location: This adjusts the rising edge of the XLAT pulse location. It is relative to the rising edge ofthe BLANK signal. A negative XLAT Location is shown when the XLAT signal rises before the BLANKsignal.
Default Values: This box resets all Timing Controls to their default values.
When not checked, the EVM does not supply power to the TLC5944 VUP pins. This allows the LEDs toshow ghosting in the ghosting demo. When checked, the EVM applies power to the TLC5944 VUP pinswhich enables the Pre-Charge FETs to eliminate the visible ghosting.
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3.2.6 Ghosting Demo
www.ti.com Operation
Figure 3. TLC5944EVM Software with Ghosting Demo Enabled.
When not checked, the EVM GUI is configured as shown in Figure 3 . The GUI commands the EVM toonly supply power to the Row A LEDs. When checked, the GUI reconfigures itself as shown in Figure 3 .The GUI now commands the EVM to switch power back and forth between the Row A and Row LEDs.The LED Board and Timing Control Settings are optimized to show visible ghosting. When the GhostingDemo is enabled, the red LEDs in Row B are visually illuminated, even when programmed to be off. Theuser can now program the Row A and Row B LEDs separately. Note that Row B LEDs are red and canonly be programmed with a red intensity value between 0 and 4095 with the Intensity field in the Row Bwindow.
WARNINGWhen using the Ghosting Demo, the input voltage must be lessthan 10 V.
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3.2.7 LED Frames
3.2.8 File – Save and Load
3.2.9 View – Editing Radix
3.2.10 View – LED Display Mode
3.2.11 Tools – Update DSP Firmware
3.2.12 Information Bar – EVM Status
Operation www.ti.com
The LED tool bar provides many easy-to-use functions to facilitate the EVM’s evaluation. Each button hasa pop-up description, which makes each function self-explanatory.
This tab allows the user to save and load custom frames. The file also saves all user-selectable settingssuch as operating frequency and Dot Correction settings.
Changes the input format for the PWM Grayscale values in the Color Picker and Dot Correction Valuesbetween Hex, Percentage, and Absolute.
When Solid display mode is chosen, the pixel in the LED Frames window shows the LED pixels and theirapproximate color on the EVM. This color is generated by the mixing of the three individual LED colors.When RGB display mode is chosen, the pixel shows the relative intensity of each individual LED thatmakes up each pixel.
Clicking on this function provides step-by-step directions on how to update the EVM’s DSP firmware.
The information bar displays whether or not the GUI detects the EVM hardware.
Figure 4. Information Bar
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