NEC Network Controller uPD98502 User Manual
Page 249
CHAPTER 4 ATM CELL PROCESSOR
Preliminary User’s Manual S15543EJ1V0UM
249
4.5.1.1 Packet descriptor
A packet descriptor contains two words shown as Figure 4-10. Its address is word aligned.
Figure 4-10. Tx Packet Descriptor
-Tx packet descriptor
31
0
16 15
Attribute
CPCS-UU
CPI
8 7
16
GFC
28
CLPM
27
PTI
26
24
23
19
18
17
20
IM
C10
AAL
MB
Directory Address
31
0
31
1
30
ENC
29
Table 4-1 is a list of Tx packet attributes. Detail will be given in Operation chapter.
Table 4-1. List of Tx Packet Attribute
Field
Description
ENC
It contains Encapsulation bits to specify Encapsulation modes.
CLPM
It contains CLP bit to be set in Tx cell header.
PTI
It contains PTI bit to be set in Tx cell header.
GFC
It contains GFC bit to be set in Tx cell header.
IM
It disables interruption and indication when Tx is completed.
C10
It enables generation and insertion of CRC10 code.
AAL
It specifies type of AAL.
MB
It indicates the number of mailbox.
CPCS-UU
It contains CPCS-UU bits to be set in Tx cell trailer.
CPI
It contains CPI bits to be set in Tx cell trailer.