MC68181 Datasheet, PDF (100/119 Pages) Freescale Semiconductor, Inc – Advance Information ROAMING FLEX chip SIGNAL PROCESSOR

MC68181
Freescale Semiconductor, Inc.
Decoder-to-Host Packet Descriptions
NEXT ASSIGNED FRAME (NAF)
This is the frame number of next frame the FLEX chip IC was scheduled to decode
when the receiver shut down. The value of this field is valid only if the FLEX chip IC
is in synchronous mode and the FIV bit in the status packet is set. When in
asynchronous mode this value will be 0.
Status Packet
The Status Packet contains various types of information that the host may require.
The Status Packet will be sent to the host whenever the FLEX chip IC is polled and
has no other data to send. The FLEX chip IC can also prompt the host to read the
Status Packet due to events for which the FLEX chip IC was configured to send it
(see Configuration Packet on page B-8 and Control Packet on page B-11 for a
detailed description of the bits). The FLEX chip IC prompts the host to read a Status
Packet if one of the following is true:
• The MT bit in the Status Packet and the MTE bit in the Configuration Packet
are set.
• The EOF bit in the Status Packet is set.
• The LBU bit in the Status Packet is set.
• The EA bit in the Status Packet is set.
• The BOE bit in the Status Packet is set.
The ID of the Status Packet is 127 (decimal)
.
Table B-43 Status Packet Bit Assignments
Byte
3
2
1
0
Bit 7
0
FIV
SM
SMU
Bit 6
1
f₆
LB
LBU
Bit 5
1
f₅
x
x
Bit 4
1
f₄
x
MT
Bit 3
1
f₃
c₃
x
Bit 2
1
f₂
c₂
EOF
Bit 1
1
f₁
c₁
EA
Bit 0
1
f₀
c₀
BOE
FRAME INFO VALID (FIV)
The FIV bit is set when a valid frame info word has been received since becoming
synchronous to the system and the f and c fields contain valid values. If this bit is
clear, no valid frame info words have been received since the FLEX chip IC became
synchronous to the system. This value will change from 0 to 1 at the end of block 0 of
the frame in which the 1st frame info word was properly received. It will be cleared
when the FLEX chip IC goes into Asynchronous mode. This bit is initialized to 0
B-40
MC68181 Technical Data Sheet
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