mc68181 Freescale Semiconductor, Inc, mc68181 Datasheet - Page 99

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

Receiver Shutdown Packet
MOTOROLA
RECEIVED SYSTEM COLLAPSE (RSC)
FRAME NUMBER VALID (FNV)
CURRENT FRAME (CF)
TIME TO NEXT FRAME (TNF)
FRAME CARRIED ON FCO)
Byte
3
2
1
0
When SCU is set, this value represents the system collapse value that was received in
the frame.
The Shutdown Packet is sent in both synchronous and asynchronous mode. It is
designed to indicate to the host that the receiver is turned off and how much time
there is until the FLEX chip will automatically turn it back on.
This bit is set if the last frame info word was correctable and the frame number was
the expected value. When in asynchronous mode, this value will be 0.
When in synchronous mode, this is the current frame number. This value is latched
on the negative edge of the READY line when this packet is sent to the host. 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.
When in synchronous mode TNF indicates the time to the start of the A-word check if
the FLEX chip IC were to warm up for the next frame. When in asynchronous mode
TNF indicates the time to the start of the next automatic noise detect. See Using the
Receiver Shutdown Packet on page C-12 for an explanation on how to use this
value. This value is latched on the negative edge of the READY line when this packet
is sent to the host.
This bit is set if the FLEX chip IC is decoding the next frame due to the reception of a
non-zero carry-on value in a previous frame. When in asynchronous mode, this value
will be 0.
TNF
Bit 7
FNV
FCO
0
Table 2-42 Receiver Shut Down Packet Bit Assignments
7
Freescale Semiconductor, Inc.
For More Information On This Product,
NAF
TNF
Bit 6
CF
MC68181 Technical Data Sheet
1
6
6
6
Go to: www.freescale.com
NAF
TNF
Bit 5
CF
1
5
5
5
NAF
TNF
Bit 4
CF
1
4
4
4
NAF
Bit 3
TNF
CF
1
Decoder-to-Host Packet Descriptions
3
3
3
NAF
TNF
Bit 2
CF
1
2
2
2
NAF
TNF
Bit 1
CF
1
1
1
1
NAF
TNF
Bit 0
MC68181
CF
0
0
B-39
0
0