cx28560 Mindspeed Technologies, cx28560 Datasheet - Page 233

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

CX28560 Data Sheet
C.2
28560-DSH-001-B
Example
Take, for example, a channel that has just been activated, so the internal buffer is
empty. The free space counter for that channel should be set to the size of the buffer
allocated in the Buffer Size register
FRAGLEN is the number of bytes in the fragment.
When a fragment of length FRAGLEN is sent to the CX28560, not containing an end
of message, the free space counter should be decremented by FRAGLEN / 4 (this will
be the whole number MAXFRAGLEN/4).
When a fragment of length FRAGLEN is sent to the CX28560, containing an end of
message, the free space counter should be decremented by:
Switch (FRAGLEN % 4)
When a report is received, the counter should be incremented by the value received in
the report of the number of words sent (WSENT). This value of WSENT takes into
consideration the storage of command bytes in the internal buffer, so no further
calculation is required.
Case 1: (FRAGLEN + 3) / 4
Case 2: (FRAGLEN + 2) / 4
Case 3: (FRAGLEN + 5) / 4
Case 4: (FRAGLEN + 4) / 4
Mindspeed Technologies™
Advance Information
(Chapter
5.0, RBUFFC Data FIFO Size Register).
Flow Conductor Interface
C
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