NEC Network Controller uPD98502 - Manual (Page 242)

CHAPTER 4 ATM CELL PROCESSOR
242 Preliminary User’s Manual S15543EJ1V0UM
4.4.5 A_RQU (Receiving Queue Underrun Register)
A_RQU shows the status of each pool. When a pool has no free buffers, the corresponding bit is set. ATM Cell
Processor detects a pool empty when it receives a cell and try to send the cell to buffer. Whenever one of A_RQU bits
is set, A_RQU bit in A_GSR will be set. In this block, only pool7 to pool0 will be used. If a bit is set to ‘1’,
corresponding pool has no free buffers. Initial value is all zero.
Bits Field R/W Default Description
31:8 Reserved R 0 Reserved for future use
7:0 A_RQU[7:0] R 0 0 = pool [7:0] has free buffers
1 = pool [7:0] has no free buffers
4.4.6 A_RQA (Receiving Queue Alert Register)
A_RQA shows pools with less remaining batches than “ALERT LEVEL”, which is set by V
R
4120A. Whenever one
of A_RQA bits is set, A_RQA bit in A_GSR will be set. In this block, only pool7 to pool0 will be used. If a bit is set to
‘1’, the number of remaining batches is less than “ALERT LEVEL”. Initial value is all zero.
Bits Field R/W Default Description
31:8 Reserved R 0 Reserved for future use
7:0 A_RQA[7:0] R 0 0 = pool [7:0] has more or equal remaining batches than “ALERT LEVEL”
1 = pool [7:0] has less remaining batches than “ALERT LEVEL”
4.4.7 A_VER (Version Register)
A_VER shows version number of ATM Cell Processor block. Initial value is 0000_0200H.
Bits Field R/W Default Description
31:16 Reserved R 0 Reserved for future use
15:8 MAJOR R 02H Major revision
7:0 MINOR R 00H Minor revision
4.4.8 A_CMR (Command Register)
ATM Cell Processor receives command and parameter when V R 4120A writes them in A_CMR and A_CER. ATM
Cell Processor can handle only one command at a time. When ATM Cell Processor receives a command from
V
R
4120A, it sets Busy Flag in the register automatically to indicate it is busy. While Busy Flag is set, ATM Cell
Processor can not receive a new command. If V
R
4120A writes a new command when Busy Flag is set, the new
command will be ignored. Initial value is zero. Detail of this register is described in Section 4.7 Commands.
Bits Field R/W Default Description
31 BSY R/W 0 Busy Flag
30:0 A_CMR R/W 0 Command and parameter
4.4.9 A_CER (Command Extension Register)
Command Extension Register. Initial value is zero. Detail of this register is described in Section 4.7 Commands.
Bits Field R/W Default Description
31:0 A_CER R/W 0 Parameter of command