mc68181 Freescale Semiconductor, Inc, mc68181 Datasheet - Page 34

• Manufacturer Part Number: mc68181
• Description: Signal Processor
• Manufacturer: Freescale Semiconductor, Inc

MC68181
FLEX Frame Structure
A-6
BLOCK INFORMATION FIELD
ADDRESS FIELD
VECTOR FIELD
MESSAGE FIELD
IDLE FIELD
The boundaries between the fields are independent of the block boundaries.
Furthermore, at 3200 and 6400 bps, the information in one phase is independent of
the information in a concurrent phase, and the boundaries between the fields of one
phase are unrelated to the boundaries between the fields in a concurrent phase.
The block information field may contain information words for determining time and
date information and certain paging system information.
The address field contains addresses assigned to paging devices. Addresses are used
to identify information sent to individual paging devices and/or groups of paging
devices. An address may be either a “short” one word address or a “long” two word
address. Information in the FLEX signal may indicate that an address is a priority
address. An address may be a “tone only” address, in which case there is no
additional information associated with the address.
The vector field consists of a series of vector words. Depending upon the type of
message, a vector word (or words in the case of a long address) may either contain all
of the information necessary for the message, or indicate the location of message
words in the message field comprising the message information. If an address is not a
tone only address, then there is an associated vector word in the vector field.
Information in the FLEX signal indicates the location of the vector word. Short
addresses have one associated vector word and long addresses two associated vector
words. A pager may go to low power mode at the end of the address field if its
address(es) is (are) not detected, thus resulting in battery savings.
The message field consists of a series of information words containing message
information. The message information may be formatted in ASCII, BCD, or binary
depending upon the message type. The following sections provide a detailed
description of the various types of information words that may be used in the
message field.
The idle field is used to separate blocks.
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Block information field
Address field
Vector field
Message field
Idle field
MC68181 Technical Data Sheet
Freescale Semiconductor, Inc.
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Go to: www.freescale.com
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