28478G-18 Mindspeed Technologies, 28478G-18 Datasheet - Page 144

• Manufacturer Part Number: 28478G-18
• Description: Multichannel Synchronous Communications Controller 208-Pin BGA
• Manufacturer: Mindspeed Technologies

Specifications of 28478G-18

• Package: 208BGA
• Maximum Data Rate: 32768 Kbps
• Transmission Media Type: Wire
• Power Supply Type: Analog
• Typical Supply Current: 250 mA
• Typical Operating Supply Voltage: 3.3 V
• Minimum Operating Supply Voltage: 3 V
• Maximum Operating Supply Voltage: 3.6 V

6.3.17.2
The following describes what MUSYCC does when the receive channel is deactivated:
1. Current message processing is terminated destructively; that is, data can be lost and messages prematurely
2. The bit-level processor responsible for handling inbound bits from the serial port is immediately and
3. The channel direction remains in the suspended state until the channel is activated. The current channel
6.3.18
A channel jump request is issued by the host via a service request. For a receiver, channel jumps are the same as
channel activation.
For a transmitter, channel jumps are non-destructive to currently serviced messages. The channel state is not reset
as in the channel activate sequence. Therefore, a transmitter channel must be activated first, then subsequent
jump requests can be made using the channel jump service request. For a transmitter, channel jumps provide a
non-destructive way to start transmitting a new message list. MUSYCC waits until the completion of the current
message before jumping to a message list pointed to by a new Head Pointer.
A jump request is issued by the host via a service request towards a channel in a channel group in MUSYCC.
6.3.19
Each serial port frame consists of a fixed number of bits grouped into time slots according to the frame alignment
supplied by the serial port TSYNC and RSYNC signals. MUSYCC must be provided at least one external
synchronization pulse on the TSYNC and RSYNC input pins after the respective channel group is enabled. After
this initial sync pulse, MUSYCC tracks subsequent serial port frame boundaries using its internal flywheel
mechanism or the next applied sync pulse.
In addition to tracking serial port frame boundaries, the internal flywheel generates a frame synchronization signal
that can be selected to control the channel group's alignment of Transparent mode channel data streams. By
default, the frame synchronization signal from the internal flywheel determines Transparent mode channel data
stream alignment. If external data stream synchronization is preferred, the SFALIGN bit field in the Group
Configuration Descriptor can be set to expect this synchronization signal to come from the serial port TSYNC and
RSYNC input pins. While SFALIGN is set, the internal flywheel continues to operate, but the synchronization signal
from the flywheel is not used to determine data stream alignment. Instead, alignment is provided by the external
framer device which is allowed to strobe the sync input pins at periodic frame intervals or at any desired multiple of
the frame interval (i.e., superframe).
Each serial port frame carries stream data from one or more packetized HDLC or unpacketized Transparent mode
channels. Although channels are mapped to specific time slots within the serial port frame, each channel's data
28478-DSH-002-E
aborted.
asynchronously disabled. Data transfers to shared memory are halted.
direction configuration is maintained.
NOTE:
NOTE:
Receive Channel Deactivation
Channel Jump
Frame Alignment
Preliminary Information / Mindspeed Proprietary and Confidential
The service request acknowledge (via the SACK Interrupt Descriptor) for the jump service
request—specifically for the transmit direction—will not be output towards the host until
after the current message is transmitted. For applications with long messages to transmit,
the jump service request must be used with care.
Nx64 serial port mode does not operate the internal flywheel and therefore requires
periodic TSYNC and RSYNC pulses to keep track of serial port frame boundaries.
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Basic Operation
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