Texas Instruments TCA8424 User Manual

User's Guide

SCDU004–March 2013

TCA8424 Evaluation Module

This document is the EVM user guide for the TCA8424. The device is a low-voltage keyboard scanner that can support up to 128 keys, with open drain outputs that can sink up to 12 mA of current for LEDs. The TCA8424 is fully HID over I2C™ compliant and is available with a pre-programmed keyboard map.

Contents

1 About this Manual ........................................................................................................... 2

2 Information about Cautions and Warnings .............................................................................. 2

3 FCC Warning ................................................................................................................ 2

4 Items Required for Operation ............................................................................................. 3

5 Introduction .................................................................................................................. 3

6 TCA8424 EVM Design Circuitry, Bill of Materials, and Connection Descriptions .................................. 4

6.1 TCA8424 EVM Schematic ........................................................................................ 4

6.2 Printed-Circuit Board (PCB) Layout ............................................................................. 5

6.3 Bill of Materials ..................................................................................................... 9

6.4 VCC and GND Connections .................................................................................... 11

6.5 MSP430 Launchpad Interface .................................................................................. 11

6.6 Breakout Pins ..................................................................................................... 12

6.7 LED Outputs ...................................................................................................... 13

7 Launchpad Software Setup .............................................................................................. 14

8 GUI Software Setup ....................................................................................................... 16

9 GUI Walkthrough Guide .................................................................................................. 17

10 Related Documentation ................................................................................................... 30

1 TCA8424 EVM Schematic................................................................................................. 4

2 Layer 1 Top Side: 50-Ω Signal Layer .................................................................................... 5

3 Layer 2 (Int1): Ground Plane.............................................................................................. 6

4 Layer 3 (Int2): 50-Ω Signal with Ground Fill............................................................................. 7

5 Layer 4 Bottom Layer ...................................................................................................... 8

6 VCC and GND Connections ............................................................................................. 11

7 MSP430 Launchpad Interface ........................................................................................... 11

8 Breakout Pins .............................................................................................................. 12

9 LED Outputs ............................................................................................................... 13

1 Bill of Materials.............................................................................................................. 9

2 Header Configurations for P1, P2, and P7............................................................................. 12

SCDU004–March 2013 TCA8424 Evaluation Module

Submit Documentation Feedback

List of Figures

List of Tables

About this Manual

1 About this Manual

This user’s guide describes the TCA8424 Evaluation Module (EVM). This guide contains the EVM schematics, bill of materials, and top and bottom board layouts.

2 Information about Cautions and Warnings

This section describes the jumpers and connectors on the EVM as well and how to properly connect, set up, and use the TPS22985EVM.

This EVM contains components that can potentially be damaged by electrostatic discharge. Always transport and store the EVM in its supplied ESD bag, when not in use. Handle using an antistatic wristband. Operate on an antistatic work surface. For more information on proper handling, see the Electrostatic Discharge (ESD) application note (SSYA008).

www.ti.com

CAUTION

The information in a caution or a warning is provided for your protection. Please read each caution and warning carefully.

3 FCC Warning

This equipment is intended for use in a laboratory test environment only. It generates, uses, and can radiate radio frequency energy and has not been tested for compliance with the limits of computing devices pursuant to subpart J of part 15 of FCC rules, which are designed to provide reasonable protection against radio frequency communications, in which case the user, at their own expense is required to take whatever measures necessary to correct this interference.

TCA8424 Evaluation Module SCDU004–March 2013

Submit Documentation Feedback

www.ti.com

4 Items Required for Operation

The following items are required to program a TCA8424:

• TCA8424 EVM with un-programmed TCA8424 in socket

• Single 3.3-V supply

• MSP-EXP430G2 Rev 1.5 Launchpad with MSP430G2553 installed

• USB to mini-USB cable

• PC with Code Composer Studio installed running supplied firmware

• PC with Application GUI installed The following items are required to evaluate at the system level:

• TCA8424 EVM with programmed TCA8424 in socket

• Breakout wires to connect to keyboard matrix rows and columns

• Keyboard matrix

• Host system with I2C plus INT connected to board

5 Introduction

The benefits of the TCA8424 over other microcontroller-based solutions are lower development costs, smaller package, and lower power consumption. The lower development costs are seen due to the TCA8424 requiring programming of only 512 Bytes of OTP versus a full code stack on a microcontroller. The TCA8424 is fully compliant with HID over I2C based systems with little to no host firmware development.

The TCA8424 can also be used in a non-Hid over I2C environment by developing host drivers that mimic the HID over I2C protocol to interpret the input reports. The EVM features a socket to allow easy programming of multiple units for testing. The code stack supplied with the EVM is designed to interface with the MSP430G2553 Launchpad to accomplish this. Once programmed, the EVM features breakout headers for the keyboard and I2C connections to test in customer systems.

Items Required for Operation

SCDU004–March 2013 TCA8424 Evaluation Module

Submit Documentation Feedback

TCA8424 EVM Design Circuitry, Bill of Materials, and Connection Descriptions

6 TCA8424 EVM Design Circuitry, Bill of Materials, and Connection Descriptions

6.1 TCA8424 EVM Schematic

Figure 1 shows the schematic for the EVM. The connections on the EVM are briefly explained in the

subsequent sections.

www.ti.com

TCA8424 Evaluation Module SCDU004–March 2013

Figure 1. TCA8424 EVM Schematic

Submit Documentation Feedback

www.ti.com

TCA8424 EVM Design Circuitry, Bill of Materials, and Connection Descriptions

6.2 Printed-Circuit Board (PCB) Layout

Figure 2 to Figure 5 show the PCB layouts for the TCA8424 EVM.

Figure 2. Layer 1 Top Side: 50-Ω Signal Layer

SCDU004–March 2013 TCA8424 Evaluation Module

Submit Documentation Feedback

TCA8424 EVM Design Circuitry, Bill of Materials, and Connection Descriptions

www.ti.com

TCA8424 Evaluation Module SCDU004–March 2013

Figure 3. Layer 2 (Int1): Ground Plane

Submit Documentation Feedback

www.ti.com

TCA8424 EVM Design Circuitry, Bill of Materials, and Connection Descriptions

Figure 4. Layer 3 (Int2): 50-Ω Signal with Ground Fill

SCDU004–March 2013 TCA8424 Evaluation Module

Submit Documentation Feedback

TCA8424 EVM Design Circuitry, Bill of Materials, and Connection Descriptions

www.ti.com

TCA8424 Evaluation Module SCDU004–March 2013

Figure 5. Layer 4 Bottom Layer

Submit Documentation Feedback

www.ti.com

TCA8424 EVM Design Circuitry, Bill of Materials, and Connection Descriptions

6.3 Bill of Materials

Table 1 is the bill of materials for this EVM.

Table 1. Bill of Materials

ITEM QTY MFG MFG PART# REF DES DESCRIPTION 1 4 PANASONIC LNJ308G8PRA LED1, LED2, LED3, LED4 LED,SMT,0603,PURE GREEN,2.03V 2 1 POMONA ELECTRONICS 2269-0 J1 DUAL INSULATED BANANA JACKS,

BLACK, 0.75LS

3 1 PANASONIC ECJ-1V41E105M C4, C5, C6, C7, C8, C9, C10, C11, CAPACITOR,SMT,0603,CERAMIC,1.0u

F,25V,20%,X5S

4 1 PANASONIC ECJ-1VB0J106M C12 CAPACITOR,SMT,0603,CERAMIC,10u

F,6.3V,20%,X5R

5 1 TAIYO YUDEN TMK107SD472JA C2 CAPACITOR,SMT,0603,CERAMIC,470

0pF,25V,5%,SD 6 1 VISHAY SPRAGUE 594D687X0010R2T C3 CAP,TAN,SMT,10V,20%, 680uF 7 1 PANASONIC EEFUD0K101R C1 CAP,SMT,ELE,100uf,8V,20% 8 1 DIODES INC B230-13-F CR2 DIODE,SCHOTTKY,SMT, DIODES,INC. 9 1 DIODES INC SD103CW-13-F CR1 SCHOTTKEY

DIODE,SMT,20V,400mW,SOD-123 10 1 SAMTEC TSW-104-07-G-D P2 HEADER,THU,8P,2X4,MALE,DUAL

ROW,100LS,100TL 11 1 SAMTEC TSW-108-07-G-D P1 HEADER,THU,16P,2X8,MALE,DUAL

ROW,100LS,100TL 12 2 FCI 66951-010LF P8, P9 HEADER,THU,10P,1X10,FEMALE,SIN

GLE ROW,100LS,200TL 13 6 SAMTEC TSW-101-07-G-S P3, P4, P5, P6, P10, P11 HEADER,THU,1P,MALE,SINGLE

ROW,100TL 14 5 TE Connectivity 9-146281-0-02 P12, P13, P14, P15, P16 15 1 TE Connectivity 9-146281-0-04 P17 16 1 *ENPLAS CORPORATION QFN-40B-0.5-01 DUT3 HTSOCKET,QFN,40P,35x29x16.7mm,

w 2.1hole 17 1 TI TPS77001DBV U2 1.2~5.5V,ULTRALOW-POWER 50mA

LOW-DROP LINE REGULATOR 18 1 TI TPS27081ADDCR U3 HIGH SIDE LOAD SWITCH WITH LVL

SHFT AND ADJ SLEW RATE 19 1 TI LM2700MTX-ADJ/NOPB U4 LM2700 600KHZ/1.25MHZ,2.5A,

STEPUP PWM DC/DC CONVERTER 20 1 BOURNS SDR0805-100ML L1 INDUCTOR,SMT,2P,POWER,10uH,20

%,RoHS 21 1 VISHAY CRCW060310K0FKEA R21 RESISTOR,SMT,0603,1%,1/10W,10.0K 22 3 VISHAY CRCW0603100KFKEA R10, R11, R12 RESISTOR,SMT,0603,1%,1/10W,100K 23 1 VISHAY CRCW06031K02FKEA R3 RESISTOR,SMT,0603,1%,1/10W,1.02K 24 1 VISHAY CRCW0603150KFKEA R9 RESISTOR,SMT,0603,1%,1/10W,150K 25 1 VISHAY CRCW0603169KFKEA R8 RESISTOR,SMT,0603,1%,1/10W,169K 26 1 VISHAY CRCW060320K0FKEA R15 RESISTOR,SMT,0603,1%,1/10W,20.0K 27 1 VISHAY CRCW06034K64FKEA R2 RESISTOR,SMT,0603,1%,1/10W,4.64K 28 4 PANASONIC ERJ-3GSYJ121 R4,R5, R6, R7 RESISTOR,SMT,0603,5%,1/10W,120

SCDU004–March 2013 TCA8424 Evaluation Module

Submit Documentation Feedback

TCA8424 EVM Design Circuitry, Bill of Materials, and Connection Descriptions

www.ti.com

Table 1. Bill of Materials (continued)

29 5 PANASONIC ERJ-3GSYJ122 R16,R17, R18, R19, R20 RESISTOR,SMT,0603,5%,1/10W,1.2K 30 0 BOURNS 3313J-1-204 R14 PlaceHolder, DO NOT INSTALL 32 0 PANASONIC ECJ-1V41E105M C13 PlaceHolder, DO NOT INSTALL 33 1 Texas Instruments TCA8424RHAR U1 TIdevice to be used in Socket 34 5 TE Connectivity 382811-8 N/A Jumpers to be installed over P12, P13,

P14, P15, P16

TCA8424 Evaluation Module SCDU004–March 2013

Submit Documentation Feedback

+ 22 hidden pages

Texas Instruments TCA8424 User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual