K60P100M100SF2RM Datasheet, PDF (1085/1809 Pages) Freescale Semiconductor, Inc – K60 Sub-Family Reference Manual

Chapter 42
Carrier Modulator Transmitter (CMT)
42.1 Introduction
NOTE
For the chip-specific implementation details of this module's
instances see the chip configuration chapter.
The carrier modulator transmitter (CMT) module provides means to generate the protocol
timing and carrier signals for a wide variety of encoding schemes. The CMT incorporates
hardware to off-load the critical and/or lengthy timing requirements associated with
signal generation from the CPU, releasing much of its bandwidth to handle other tasks
such as code data generation, data decompression, or keyboard scanning. The CMT does
not include dedicated hardware configurations for specific protocols but is intended to be
sufficiently programmable in its function to handle the timing requirements of most
protocols with minimal CPU intervention. When the modulator is disabled, certain CMT
registers can be used to change the state of the infrared output (CMT_IRO) signal
directly. This feature allows for the generation of future protocol timing signals not
readily producible by the current architecture.
42.2 Features
The features of this module include:
• Four modes of operation
• Time; with independent control of high and low times
• Baseband
• Frequency shift key (FSK)
• Direct software control of CMT_IRO signal
K60 Sub-Family Reference Manual, Rev. 6, Nov 2011
Freescale Semiconductor, Inc.
1085