Introduction
1.1
Features
•
Works with MSP430 Launchpad
•
Illustrates the use of TPL0401DPOT for color mixing
•
TCA7408 used for Key press detection
•
Shows the use of Single wire self timed interface in TCA5405
•
Color mixing and LED blinking control
1.2
TPL0401A/B
The TPL0401 is an I2C bus controlled, single channel, linear-taper digital potentiometer with 128 wiper
positions. TPL0401A/B have an end-to-end resistance of 10k ohms and the low terminal internally
connected to ground.
1.3
TCA5405
The TCA5405 is a 5-bit output expander controlled using a single wire input. This device is ideal for
portable applications as it has a wide VCC range of 1.65V to 3.6 V. The TCA5405 uses a self-timed serial
data protocol with a single data input driven by a master device synchronized to an internal clock of that
device.
1.4
TCA7408
This 8-bit I/O expander for the two-line bidirectional bus (I
2
C) is designed to provide general-purpose
remote I/O expansion via the I
2
C interface [serial clock (SCL) and serial data (SDA)]. The major benefit of
this device is its wide VCC range. It can operate from 1.65-V to 3.6-V on the GPIO-port side and 1.65-V to
5.5-V on the SDA/SCL side. This allows the TCA7408 to interface with next-generation microprocessors
and microcontrollers on the SDA/SCL side, where supply levels are dropping down to conserve power.
The TCA7408 open-drain interrupt (INT) output is activated when any GPIO set as an input has a
transition to the state opposite of that in the Input Default State register and the corresponding bit in the
Interrupt Mask Register is set to 0. It is used to indicate to the system master that an input has changed to
a pre-determined state.
1.5
TLC59108
The TLC59108 is an I
2
C bus controlled 8-bit LED driver that is optimized for red/green/blue/amber (RGBA)
color mixing and backlight application for amusement products. Each LED output has its own 8-bit
resolution (256 steps) fixed-frequency individual PWM controller that operates at 97 kHz, with a duty cycle
that is adjustable from 0% to 99.6%. The individual PWM controller allows each LED to be set to a specific
brightness value. An additional 8-bit resolution group PWM controller has both a fixed frequency of 190 Hz
and an adjustable frequency between 24 Hz to once every 10.73 seconds, with a duty cycle that is
adjustable from 0% to 99.6%. The group PWM controller dims or blinks all LEDs with the same value.
TLC59108 scales up the reference current set by the external resistor (Rext) to sink the output current
(Iout) at each output port.
1.6
Requirements
In order to operate this EVM, the following components must be connected and properly configured.
1.6.1
LaunchPad
A Texas Instruments LaunchPad (MSP-EXP430G2) with the male headers and an MSP430G2553
microcontroller installed is required to run the board. A LaunchPad can be acquired here
(
https://estore.ti.com/MSP-EXP430G2-MSP430-LaunchPad-Value-Line-Development-kit-P2031.aspx
)
NOTE: IMPORTANT: The code to control the TCA7408EVM/TCA5405EVM was written from an
MSP430G2553 and will not work with the MSP430 chips that are included with the
LaunchPad kit.
2
TCA7408EVM,TCA5405EVM
SCPU034
–
December 2011
Copyright
©
2011, Texas Instruments Incorporated
