Texas Instruments TCA8418 I2C User manual

TCA8418 I2C Controlled Keypad Scan IC
Evaluation Module
User's Guide
Literature Number: SCPU033
May 2010

2SCPU033–May 2010
Copyright © 2010, Texas Instruments Incorporated

Preface ....................................................................................................................................... 5
1 Introduction ........................................................................................................................ 7
1.1 List of Hardware Items for Operation ................................................................................. 7
1.2 List of Software Items for Operation .................................................................................. 7
1.3 Step-by-step Instructions for Operation and Troubleshooting ..................................................... 7
1.4 Hardware Uninstall Instructions ....................................................................................... 7
1.5 Software Uninstall Instructions ........................................................................................ 8
2 EVM Configuration and Description ....................................................................................... 8
2.1 EVM Options ............................................................................................................. 8
2.2 EEPROM (U1) and JMP10 ............................................................................................. 8
2.3 LED (D1) Indication of USB Attached ................................................................................ 8
2.4 Test Point Connectors (TP1 through TP5) ........................................................................... 8
2.5 Jumper Configuration (JMP1 through JMP6) ........................................................................ 9
2.6 Schematics ............................................................................................................. 12
2.7 Bill of Materials ......................................................................................................... 14
3 GUI Configuration and Description ...................................................................................... 16
3.1 GUI Installation ......................................................................................................... 16
3.2 GUI Functionality ....................................................................................................... 17
3.2.1 Keypad Mode ............................................................................................... 17
3.2.2 Overflow Mode ............................................................................................. 18
3.2.3 GPIO Mode ................................................................................................. 19
3.2.4 Registers and I2C........................................................................................... 20
4 Related Documentation from Texas Instruments ................................................................... 21
3
SCPU033–May 2010 Table of Contents
Copyright © 2010, Texas Instruments Incorporated

www.ti.com
List of Figures
1 Jumper Configuration: JMP1 and JMP2................................................................................ 10
2 Jumper Configuration: JMP3 and JMP4................................................................................ 10
3 Jumper Configuration: JMP5............................................................................................. 11
4 Jumper Configuration: JMP6, JMP7, JMP8, JMP9 ................................................................... 11
5 Schematics (1 of 2)........................................................................................................ 12
6 Schematics (2 of 2)........................................................................................................ 13
7 TCA8418 EVM GUI Files................................................................................................. 16
8 TCA8418 EVM Application Installation ................................................................................. 16
9 TCA8418 EVM GUI: Keypad Mode..................................................................................... 17
10 TCA8418 EVM GUI: Overflow Mode.................................................................................... 18
11 TCA8418 EVM GUI: GPIO Mode ....................................................................................... 19
12 TCA8418 EVM GUI: Registers and I2C................................................................................. 20
List of Tables
1 Test Point Descriptions..................................................................................................... 8
2 Jumper Descriptions........................................................................................................ 9
3 Bill of Materials............................................................................................................. 14
4List of Figures SCPU033–May 2010
Copyright © 2010, Texas Instruments Incorporated

Read This First
SCPU033–May 2010
Preface
About This Manual
This user guide describes the functions and operation of TCA8418 Evaluation Module (EVM), including
hardware design, graphical user interface (GUI), and EVM setup.
How to Use This Manual
This document contains the following chapters:
• Chapter 1 – Introduction and Quick Start
• Chapter 2 – EVM Configuration and Description
• Chapter 3 – GUI Configuration and Description
• Chapter 4 – Schematic and Layout
Information about Cautions and Warnings
The information in a caution or a warning is provided for your protection. Please read each caution and
warning carefully.
CAUTION
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
application report Electrostatic Discharge (ESD) (SSYA008)
CAUTION
By default, the I2C data and clock lines at TP3 and TP4 are pulled up internally
to TCA8418 supply voltage (1.8 V to 3.3 V) through jumper JMP7 configuration.
If external pullup resistors are used instead, make sure to pull up to 3.3 V only.
Operation from 5 V is not specified and may permanently damage this EVM.
All trademarks are the property of their respective owners.
5
SCPU033–May 2010 Preface
Copyright © 2010, Texas Instruments Incorporated

FCC Warning www.ti.com
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 interference. Operation of this equipment in other environments may
cause interference with radio communications, in which case the user at his/her own expense will be
required to take whatever measures may be required to correct this interference.
6Preface SCPU033–May 2010
Copyright © 2010, Texas Instruments Incorporated

User's Guide
SCPU033–May 2010
TCA8418 I2C Controlled Keypad Scan IC Evaluation
Module
1 Introduction
The TCA8418 EVM is an evaluation module (EVM) for the Texas Instruments (TI) inter-integrated circuit
(I2C) controlled keypad scan IC. The TCA8418 keypad scan IC operates from supply voltage range of 1.65
V to 3.3 V. It offers high level of electrostatic discharge (ESD) protection and supports 1-MHz Fast Mode
Plus I2C bus. With 18 configurable GPIO pins, it can be configured to support 10x8 keypad array. This
operation frees the processor from scanning the keypad for presses and releases, thus saving power and
bandwidth of the system.
The TCA8418 EVM serves as an I2C interface adapter between a host PC (IBM compatible), the
TCA8418, and/or other I2C compatible devices externally connected to the EVM. The communication
between EVM and the host PC is via USB (through a standard type-A to type-B USB cable), while the
communication between the EVM, the TCA8418, and/or other slave devices is via I2C bus. The EVM
converts communication transactions between the USB and I2C.
1.1 List of Hardware Items for Operation
To operate the TCA8418 EVM, these items are required:
• The TCA8418 EVM
• Standard type-A to type-B USB cable
• IBM compatible PC with Microsoft Windows XP or later operating system installed
1.2 List of Software Items for Operation
In addition to the hardware items listed in Section 1.1, this software is required:
• Demo GUI Software (TCA8418.exe)
The software can be downloaded from the TI website at www.ti.com.
The EVM is recognized by a PC as a generic human interface device (HID), which is supported by the
built-in USB/HID drivers of the Windows XP or later operating system. Therefore, it is plug-and-play and
no proprietary USB driver is required.
1.3 Step-by-step Instructions for Operation and Troubleshooting
After downloading and installing the GUI demo software, follow these steps to operate the EVM:
1. Plug the USB cable into both the PC and the EVM and wait for the LED to illuminate.
Troubleshooting: If the LED does not illuminate after 30 seconds, make sure that the USB cable is
securely connected. If the connection is secure, try a different USB port. If a different USB port does
not solve the problem, try to reboot the computer. If rebooting the computer does not fix the problem,
try a different USB cable. If a different USB cable does not solve the problem, contact TI technical
support for help.
2. Run the TCA8418 EVM GUI software and follow the instructions for the GUI.
1.4 Hardware Uninstall Instructions
Unplug the EVM from the USB port to uninstall the hardware from the host PC.
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SCPU033–May 2010 TCA8418 I2C Controlled Keypad Scan IC Evaluation Module
Copyright © 2010, Texas Instruments Incorporated

EVM Configuration and Description www.ti.com
1.5 Software Uninstall Instructions
For Windows operating system, go to Control Panel > Add or Remove Programs to remove the TCA8418
GUI software.
2 EVM Configuration and Description
2.1 EVM Options
The hardware is based on a USB peripheral chip from TI (TUSB3210). The TUSB3210 has an 8052 core
with enhanced performance. The PCB is a simple two-layer top-side populated board (see the schematic
in Section 2.6). The major features of the hardware design are detailed in the following sections.
2.2 EEPROM (U1) and JMP10
The embedded firmware is stored in a 64-kbit EEPROM (see U1 in the schematic in Section 2.6). The
firmware is field programmable. Jumper JMP10 is normally closed and is used for firmware development
only. On power up, the TUSB3210 downloads the firmware image from the EEPROM to the internal static
RAM and starts firmware execution (first with USB enumeration) from there.
2.3 LED (D1) Indication of USB Attached
A white LED is mounted next to the TUSB3210 IC (U4) on the evaluation board. Every time the USB
interface adapter is attached to a PC via a USB cable, and if the host PC detects it and goes through USB
enumeration successfully, the embedded firmware illuminates the white LED (D1); otherwise, the LED
remains off. After unplugging the USB cable, the LED turns off immediately.
2.4 Test Point Connectors (TP1 through TP5)
Test point connectors TP1 through TP5 allow the users to connect both external signal sources and
external I2C slave devices to the EVM. Table 1 describes the functions of all of the test points in the EVM.
Table 1. Test Point Descriptions
Test Point Functionality Configuration
To either monitor or supply to To supply TCA8418 IC reset externally , the external I/O logic level must be the
TP1 TCA8418 IC reset signal same as TCA8418 IC.
To monitor TCA8418 IC
TP2 interrupt signal
To either monitor or supply to To supply TCA8418 IC SCL externally , the external I/O logic level must be the
TP3 TCA8418 IC I2C SCL line same as TCA8418 IC.
To either monitor or supply to To supply TCA8418 IC SDA externally , the external I/O logic level must be the
TP4 TCA8418 IC I2C SDA line same as TCA8418 IC.
To either monitor or supply to To supply TCA8418 IC VCC externally , U5 must be disabled by shunting 2-3 on
TP5 TCA8418 VCC JMP4.
TP6 Ground test point
TP7 Ground test point
TP8 Ground test point
8SCPU033–May 2010
TCA8418 I2C Controlled Keypad Scan IC Evaluation Module
Copyright © 2010, Texas Instruments Incorporated

www.ti.com EVM Configuration and Description
External Microcontroller Control
The user can provide external microcontroller I2C and GPIO connections to the EVM by routing them to
test points TP1 to TP4.
Before connecting the microcontroller, check the following:
• Make sure the I/O voltage of the external microcontroller is the same as the I/O voltage of the
TCA8418. The power supply voltage of the TCA8418_VCC can be adjusted through JMP5 or
externally supplied through TP5 with U5 disabled by JMP4 (see Section 2.5).
• Make sure the external microcontroller is isolated from the TUSB3210 by disabling the TXS0104E level
translator. Shorting jumper JMP2 can disable the level translator (see Section 2.5).
External I2C Slave Devices
The user can connect external I2C slave devices to test points TP3 and TP4. The devices can be
controlled through the TCA8418 graphical user interface (GUI) software. Under the GUI software control,
the I2C bus operates at 400 kHz. Therefore, the external slave devices must support 400-kHz I2C bus.
2.5 Jumper Configuration (JMP1 through JMP6)
To use the full TCA8418 (GUI) software functionality, all jumpers except JMP5 must be at their default
settings. Table 2 describes all of the jumpers in the EVM and their respective functionality (all default
settings are in bold).
Table 2. Jumper Descriptions
Jumper Functionality Configuration
TCA8418 Keypad Scanner IC Open JMP1 to allow GUI control
JMP1 Disable Shunt JMP1 to disable TCA8418 manually
TXS0104E Level Translator Open JMP2 to enable level translation
JMP2 Disable Shunt JMP2 to disable level translation
LP2985-33 5V to 3.3V LDO Shunt JMP3 in 1-2 position to enable the 3.3V LDO
JMP3 Disable Shunt JMP3 in 2-3 position to disable the 3.3V LDO
TPS73101 5V to Variable Shunt JMP4 in 1-2 position to enable the Variable Output LDO
JMP4 Output LDO Disable Shunt JMP4 in 2-3 position to disable the Variable Output LDO
TPS73101 5V to Variable Shunt 1-2 for TCA8418_VCC = 1.8V
JMP5 Output LDO Adjust Shunt 2-3 for TCA8418_Vcc = 3.3VOpen all for TCA8418_Vcc = 2.4V
TCA8418 ROW6 Function Shunt 1-2 for GPI functionality
JMP6(1) Selection Shunt 2-3 for Keypad functionality
TCA8418 ROW7 Function Shunt 1-2 for GPI functionality
JMP7(1) Selection Shunt 2-3 for Keypad functionality
TCA8418 COL8 Function Shunt 1-2 for GPO functionality
JMP8(1) Selection Shunt 2-3 for Keypad functionality
TCA8418 COL9 Function Shunt 1-2 for GPO functionality
JMP9(1) Selection Shunt 2-3 for Keypad functionality
Open JMP6 to open EEPROM SCL line for firmware programming
JMP10 EEPROM SCL Line Short Shunt JMP4 to short EEPROM SCL line
(1) JMP6, JMP7, JMP8, and JMP9 must all have the same configuration for correct GUI operation.
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SCPU033–May 2010 TCA8418 I2C Controlled Keypad Scan IC Evaluation Module
Copyright © 2010, Texas Instruments Incorporated

10 kW
TCA8418_VCC
JMP1
To TUSB3210 To TCA8418 Enable
TCA8418_VCC
JMP2
To TXS0104E Enable
10 kW
USB_5V
JMP3 and JMP4
To LDO Enable
1
2
3
Enable
Disable
EVM Configuration and Description www.ti.com
Jumpers JMP1, JMP2, JMP3, and JMP4 allow the user to manually enable and disable TCA8418 (U3),
TXS0104E (U2), LP2988-33 (U7), and TPS73101 (U5), respectively. Jumpers JMP1 and JMP2 are
two-pin headers with pin 1 pulled up to TCA8418_VCC through 10-kΩresistors (see Figure 1). Jumpers
JMP3 and JMP4 are three-pin headers with two jumper configurations (see Figure 2).
Figure 1. Jumper Configuration: JMP1 and JMP2
To enable both the TCA8418 and the TXS0104E, leave both JMP1 and JMP2 open. Through the GUI
software, the TUSB3210 microcontroller (U4) detects the on/off state of the TCA8418 IC (U3). When
JMP1 is open, the TCA8418 EVM software has the full control of the TCA8418 IC through TUSB3210
microcontroller. To manually disable the TCA8418 IC, shunt JMP1 to drive the active-low reset input of the
TCA8418 to logic low.
JMP2 controls the TXS0104E level translator. The TCA8418 IC and other externally connected I2C slave
devices are on side A of the TXS0104E, while the TUSB3210 microcontroller is on side B of the
TXS0104E. Side A logic level is referred to the power supply level of the TCA8418, which ranges from
1.65 V to 3.6 V. As mentioned in Section 2.4, the TCA8418_VCC can be externally supplied through TP5
when TPS73101 (U5) is disabled through JMP4, or it can be supplied through the TPS73101 with output
voltages of 1.8 V, 2.3 V, or 3.3 V depending on JMP5 configuration. Side B logic level remains fixed to the
3.3-V power supply voltage of the TUSB3210.
Figure 2. Jumper Configuration: JMP3 and JMP4
If external sources of SCL, SDA, interrupt, and reset signals to the TCA8418 IC are used, disable the
TXS0104E and the TPS73101 ICs through JMP2 and JMP4 before connecting the external signals. JMP3
and JMP4 (see Figure 2) can enable or disable the output of the LP2985-33 or the TPS73101 LDO ICs.
To enable the LDOs, shunt pins 1 and 2 of the JMP3 and JMP4 to tie the enable pins of the LDO ICs to
USB_5V. To disable the LDOs, shunt pins 2 and 3 of the JMP3 and JMP4 to tie the enable pins to ground.
10 SCPU033–May 2010
TCA8418 I2C Controlled Keypad Scan IC Evaluation Module
Copyright © 2010, Texas Instruments Incorporated