cx28560 Mindspeed Technologies, cx28560 Datasheet - Page 257

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

CX28560 Data Sheet
E.5
E.5.1
E.5.1.1
Figure E-2. Worst Case on a Frame
28560-DSH-001-B
Old Frame
Service
New Frame
Service(b)
Receive Analysis
Preliminaries
2*service
Missed Services
The analysis assumes that the worst possible starting position is that a channel that has
been allocated mid-range steps has just missed a service when it accumulates its next
fragment for transmission. The scenario continues that the missed service was the last
time that the channel was to be serviced in the frame, and the system has written a
new frame to the memory.
Figure E-2
• Calculate buffer size required to contain all data that will arrive due to missed
• Compare amounts of data received between services and amount removed by
• Show that the sequence of servicing converges for 57-byte messages a check
• If, at the end of 6 services, the amount of data in the FIFO and the amount of
services.
service to check that it is not necessary to enlarge the buffer to take extra data
received into account.
whether, at any point, the sequence requires a larger buffer than the minimum.
space used in the FIFO is less than the initial conditions, proof has worked.
illustrates this specific worst case on a frame.
Mindspeed Technologies™
2*service
service
Advance Information
service
2*service
2*service
Buffer Controller FIFO Size Calculation
(a)
service
101302_021
E
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7