MC68181 Datasheet, PDF (55/119 Pages) Freescale Semiconductor, Inc – Advance Information ROAMING FLEX chip SIGNAL PROCESSOR

Freescale Semiconductor, Inc.
MC68181
FLEX Message Word Definitions
STANDARD FRAME AND PHASE EMBEDDING RULES
Maximum battery life in a FLEX decoding device is achieved when all of the
addresses assigned to a device are in the same frame. For single-phase decoding
devices, it is a requirement for all assigned addresses to be in the same phase.
Normally, it is very desirable to spread the population of FLEX subscriber units on a
system across all four phases of all 128 frames. Frame and phase spreading can be
performed automatically as addresses are assigned sequentially by embedding that
information into the 7-, 9-, and 10-digit decimal FLEX address.
The standard procedure for deriving the phase and frame values from the CAPCODE
starts by separating the 7-, 9-, or 10-digit decimal address portion (field to the right of
the CAPCODE type) and performing a decimal to binary conversion. The Least
Significant Bit (LSB) is labeled bit “0”. The following bits “2 and 3" in order, specify
phases 00, 01, 10, or 11 for phase 0,1,2,3 (a, b, c, d), and bits “4–10” represent frames
“000” through “127”.
The frame and phase can also be derived from the 7-, 9-, or 10-digit decimal address
by using modulo arithmetic (base 10) where:
Phase = (Integer (Addr/4)) Modulo 4
Frame = (Integer (Addr/16)) Modulo 128
When these rules are used, and addresses are assigned in order, the phase increments
after four consecutive addresses are assigned, while the frame is incremented after
sixteen addresses are assigned.
CAPCODE ALPHA CHARACTER DEFINITION
The alpha character in the FLEX CAPCODE indicates the type of decoding device to
which the address is assigned. The types include single-phase, any-phase, or all-
phase. It also indicates if the address is the first, second, third, or fourth address in the
subscriber unit (when addresses are assigned in order and follow standard rules),
and specifies the rules for determining in which phase and frame the address is
active.
MOTOROLA
MC68181 Technical Data Sheet
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