MC68HC05RC8 Datasheet, PDF (67/122 Pages) Freescale Semiconductor, Inc – General Release Specification

Freescale Semiconductor, Inc.
General Release Specification — MC68HC05RC16
Section 9. Carrier Modulator Transmitter (CMT)
9.1 Contents
9.2 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .67
9.3 Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .68
9.4 Carrier Generator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .70
9.4.1 Time Counter. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .71
9.4.2 Carrier Generator Data Registers (CHR1, CLR1,
CHR2, and CLR2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . .72
9.5 Modulator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .74
9.5.1 Time Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .76
9.5.2 FSK Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .77
9.5.3 Extended Space Operation . . . . . . . . . . . . . . . . . . . . . . . . .78
9.5.3.1 End Of Cycle (EOC) Interrupt . . . . . . . . . . . . . . . . . . . . .79
9.5.3.2 Modulator Control and Status Register (MCSR) . . . . . . .80
9.5.4 Modulator Period Data Registers
(MDR1, MDR2, and MDR3) . . . . . . . . . . . . . . . . . . . . . .83
9.2 Introduction
The carrier modulator transmitter (CMT) module provides a means to
generate the protocol timing and carrier signals for a wide variety of
encoding schemes. It incorporates hardware to off-load the critical
and/or lengthy timing requirements associated with code 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 disabled, certain CMT registers can be
MC68HC05RC16 — Rev. 3.0
General Release Specification
Carrier Modulator Transmitter (CMT)
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