HC05RC16GRSSLASHD datasheet(77/122 Pages) NXP

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Carrier Modulator Transmitter (CMT)

Modulator

MC68HC05RC16 — Rev. 3.0

General Release Specification

Carrier Modulator Transmitter (CMT)

Figure 9-8. CMT Operation in Time Mode

9.5.2 FSK Mode

When the modulator operates in FSK mode, the modulation mark and

space periods consist of an integer number of carrier clocks (space

period can be zero). When the mark period expires, the space period is

transparently started (as in time mode); however, in FSK mode the

carrier switches between data registers in preparation for the next mark

period. The carrier generator toggles between primary and secondary

data register values whenever the modulator mark period expires. The

space period provides an interpulse gap (no carrier), but if SBUFF = 0,

then the modulator and carrier generator will switch between carrier

frequencies without a gap or any carrier glitches (zero space).

Using timing data for carrier burst and interpulse gap length calculated

by the CPU, FSK mode can automatically generate a phase-coherent,

dual-frequency FSK signal with programmable burst and interburst

gaps.

MODULATOR GATE

fOSC ÷ 8

TIME MODE OUTPUT

BASEBAND OUTPUT

MARK

SPACE

MARK

SPACE

CARRIER FREQUENCY

Freescale Semiconductor, Inc.

For More Information On This Product,

Go to: www.freescale.com

HC05RC16GRS/D Datasheet(PDF) 77 Page - NXP Semiconductors