MC68181 Datasheet, PDF (88/119 Pages) Freescale Semiconductor, Inc – Advance Information ROAMING FLEX chip SIGNAL PROCESSOR

MC68181
Freescale Semiconductor, Inc.
Decoder-to-Host Packet Descriptions
Block Information Word Packet
The Block Information Field is the first field following the synchronization codes of
the FLEX protocol (see Appendix A). This field contains information about the frame,
such as number of addresses and messages, information about current time, the
channel ID, channel attributes, etc. The first block information word of each phase is
used internally to the FLEX chip IC and is never transmitted to the host with the
exception of the system collapse which is sent to the host when FLEX chip is in
manual collapse mode.
Time block information words 2–4 can be optionally sent to the host by setting the SBI
bit in the control packet. (see Control Packet on page B-11.) All block information
words 2–4 can be optionally sent to the host by setting the ABI bit in the roaming
control packet. When the SBI or ABI bit is set and any block information word is
received with an uncorrectable number of bit errors, the FLEX chip will send the
block information word to the host with the e bit set regardless of the value of the “f”
field in the block information word. The FLEX chip IC does not support decoding of
the vector and message words associated with the Data/System Message block info
word (f = 101). The ID of a Block Information Word Packet is 0 (decimal).
Table B-26 Block Information Word Packet Bit Assignments
Byte
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
3
0
0
0
0
0
0
0
0
2
e
p₁
p₀
x
x
f₂
f₁
f₀
1
x
x
s₁₃
s₁₂
s₁₁
s₁₀
s₉
s₈
0
s₇
s₆
s₅
s₄
s₃
s₂
s₁
s₀
Note:
e—set if more than 2 bit errors are detected in the word or if the check character calculation fails after
error correction has been performed
p—phase on which the block information word was found (0 = a, 1 = b, 2 = c, 3 = d)
x—unused bits; the value of these bits is not guaranteed
f—Word Format Type; the value of these bits modify the meaning of the s bits in this packet as
described in the following table; if the e bit is not set, this field will be one of 001, 010, or 101
s—These are the information bits of the block information word. The definition of these bits depend
on the f bits in this packet. Table B-27 on page B-29 describes the block information words that the
FLEX chip IC decodes. Refer to Appendix A for detailed information about the time-related block
information words (f = 001, 010, and 101).
B-28
MC68181 Technical Data Sheet
For More Information On This Product,
Go to: www.freescale.com
MOTOROLA