cx28560 Mindspeed Technologies, cx28560 Datasheet - Page 34

• Manufacturer Part Number: cx28560
• Description: Hdlc Controller
• Manufacturer: Mindspeed Technologies

Introduction
1.7
1.7.1
1.7.2
1-16
Data Flow
Receive Data Path
Transmit Data Path
Data enters the CX28560 via 32 independently configurable ports. Within the
CX28560 data is processed to remove HDLC formatting and to perform message error
detection (e.g., FCS error, alignment error, etc.), and concatenated to fixed length
chunks (of user-configurable length) that are then transferred to the system. The
internal memory required per channel in the CX28560 is constant, regardless of the
channel’s rate. This is achievable due to the Flexiframe algorithm (see
The Flexiframe method provides a fixed order (frame) for servicing the CX28560
channel internal buffers. The frame structure allocates service time to each channel
proportionally to its bit rate. The CX28560 runs through the frame and decides
whether or not the next channel in the frame requires servicing (i.e., whether it
contains an EOM or enough data to fill a standard fragment). If so, the data is passed
to the POS-PHY interface and is transmitted to the system.
The system stores the data until a report is received from the CX28560 via the Flow
Conductor bus. On receiving the report, the system calculates whether or not there is
room in the channel’s CX28560 internal buffer. If so, data is transferred to the
CX28560 in complete packets over the 32 bit POS-PHY interface.
The CX28560 processes the data received and outputs HDLC formatted data.
According to the Flexiframe algorithm, reports of the amount of buffer freed are
sent to the system over the dedicated 8-bit unidirectional Flow Conductor bus.
According to the reports received, the system provides fixed size fragments of data
over the 32-bit bidirectional POS-PHY bus. See
more details.
Formatted, masked, and time slot ordered data is transmitted to the line from the
CX28560 via 32 independently configurable ports.
Mindspeed Technologies™
Advance Information
Appendix B
and
Appendix C
Appendix
CX28560 Data Sheet
28560-DSH-001-B
for
B).