CN8478 Datasheet, PDF (103/221 Pages) Conexant Systems, Inc – Multichannel Synchronous Communications Controller (MUSYCC)

CN8478/CN8474A/CN8472A/CN8471A
Multichannel Synchronous Communications Controller (MUSYCC™)
5.0 Memory Organization
5.2 Descriptors
Table 5-10. Group Configuration Descriptor (2 of 2)
Bit
Field
Name
Value
Description
6
MCENBL
0
Message Configuration Bits Copy Disable. Not supported.
1
Message Configuration Bits Copy Enable. A set of configuration bits are copied from
the last transmit buffer descriptor of a message (with EOM = 1) into internal
configuration space and subsequently acted upon. The bits are used in specialized data
communications applications requiring non-default idle code transmission on a
per-message basis, inter-message pad fill, and/or message retransmission.
Direct writes to MUSYCC that change any message configuration bits remain
available. Only automatic copying from a transmit buffer descriptor (with the bit field
EOM set to 1) is disabled.
For a thorough discussion on message configuration bits see the Message
Configuration Bits subsection in the Protocol Support section.
5
MSKCOFA
0
Change of Frame Alignment Interrupt Enabled. If COFA is detected, generate Interrupt
Descriptor indicating COFA.
1
Change of Frame Alignment Interrupt Disabled. If COFA is detected, do not generate
Interrupt Descriptor.
4
MSKOOF
0
Out of Frame/Frame Recovery Interrupt Enabled—Receive Only. If OOF/FREC is
detected, generate Interrupt Descriptor indicating OOF/FREC.
1
Out of Frame/Frame Recovery Interrupt Disabled—Receive Only. If an ABT, FCS, LNG,
or ALIGN error occurs, an OFF error is reported in the interrupt descriptor and buffer
status descriptor instead of these errors.
3
OOFABT
0
OOF Message Processing Enabled—Receive Only. When OOF condition is detected,
continue processing incoming data.
1
OOF Message Processing Disabled—Receive Only. Incoming messages on all
channels are aborted when the OOF condition is detected. HDLC channels recover
automatically after the OOF condition has cleared. However, Transparent mode
channels are automatically deactivated when the OOF condition is detected, and the
host must reactivate all Transparent channels after the OOF condition has cleared.
2
SUBDSBL
0
Subchanneling Enabled. Overrides Subchannel Enable bit for all time slots and allows
subchanneling.
1
Subchanneling Disabled. Overrides Subchannel Enable bit for all time slots and
disallows subchanneling.
Using this field to disable subchanneling frees Subchannel Descriptor Map memory
space for use as an extended data buffer space.
1
TXENBL
0
Transmitter Disabled. Logically resets time slot enable bits for all time slots. Transmit
data lines are three-stated. This logical, channel-group-wide state does not affect the
bit values in any time slot map.
1
Transmitter Enabled. Logically allows all channels with time slot enable bits set to start
processing data. This logical, channel-group-wide state does not affect the bit values
in any time slot map.
0
RXENBL
0
Receiver Disabled. Logically resets time slot enable bits for all time slots. This logical,
channel-group-wide state does not affect the bit values in any time slot map.
1
Receiver Enabled. Logically allows all channels with time slot enable bits set to start
processing data. This logical, channel-group-wide state does not affect the bit values
in any time slot map.
100660E
Conexant
5-17