TI Design and Software Examples
3.1.6
IR Learning Mode Software Example
The Learning Mode example can receive IR sequences from a remote control or other device and store
them in memory associated with different buttons on the BoosterPack keypad. Then the sequences can
be transmitted from the BoosterPack by pushing the keypad buttons, and used to control IR devices.
3.1.6.1
Source File Structure
This project is organized in multiple files. This makes it easier to navigate and reuse parts of it for other
projects.
describes each file in the project.
Table 6. Source Files and Folders
Name
Description
FR4133_IR_BP_Learn.c
IR Learning mode main function, IR setup and processing, and other functions
HAL_FR4133LP_Learn_Board.c
Board initialization functions, keypad scanning functions
HAL_FR4133LP_LCD.c
LCD initialization functions, LCD display functions
3.1.6.2
IR Learning Mode Example
When the COPY button is pressed, the firmware enters learning mode. Push the button on the keypad
that you want to train, and then transmit the signal to be learned from a device like a TV remote. Continue
this until all desired buttons are assigned, and then press OK to return to normal transmit mode. Now,
when a button is pressed, the stored signal is transmitted.
While receiving signals in learning mode, the MSP430FR4133 device uses the timer capture function to
record the time between signal edges for the high and low pulses. The sequence of pulse lengths is
stored in FRAM for later use to generate the same signal when the button is pressed. For more details
about how the learning mode software works, see
.
Note that the IR receiver and demodulator on the BoosterPack is tuned for 38-kHz carrier frequency. This
is one of the most common carrier frequencies used by many remote control manufacturers for a number
of devices. If communication needs to be with a device that uses a different carrier (for example, 40 kHz),
this component can be replaced with a different receiver and demodulator device.
3.1.7
Testing
3.1.7.1
Test Environment
For current measurements
Test instrument: Fluke 87, set to µA measurement
Voltage supply at 3.3 V applied to MSP-EXP430FR4133 3V3 and GND pins on J6 of LaunchPad. All
jumpers on LaunchPad J101 removed to exclude the eZ-FET from the measurement. JP1 for LED is also
removed to remove the indicator LED (not transmission LED) from the measurement as well.
For range measurements
Measured with two MSP-EXP430 BOOST-IR, one programmed as Emitter, and one
programmed as Receiver. Environment was a normal home/office environment with normal ambient
overhead white fluorescent lighting and with no obstructions between the LaunchPads. Distance was
increased until the Receiver LaunchPad no longer received correct codes from Transmitter LaunchPad.
Range was tested with two different resistor values to show the impact of the resistor size on IR signal
strength. Changing this resistor is described in
.
20
BOOST-IR Infrared (IR) BoosterPack™ Plug-in Module
SLAU598A – December 2014 – Revised July 2015
Copyright © 2014–2015, Texas Instruments Incorporated
