NEC Network Controller uPD98502 - Manual (Page 260)

CHAPTER 4 ATM CELL PROCESSOR
260 Preliminary User’s Manual S15543EJ1V0UM
4.7.4 Tx_Ready command
The Tx_Ready command is used by the V R 4120A to notify ATM Cell Processor that a transmit packet has been
added for a specified channel (a new packet descriptor has been set in system memory queue). Upon receiving this
command, ATM Cell Processor makes the scheduling table active to perform scheduling. In this command, when it
detects some errors, writes E bit in A_CMR.
This command has the following format:
Figure 4-21. Tx_Ready Command and Indication
[Tx_Ready command]
CMR
0 1 1 0 0 1 0 VC Number 0
31 30 29 28 27 26 25 24 18 17 6 5 0
CER
Packet Descriptor Address
31 0
[Tx_Ready command indication]
CMR
0 1 1 0 0 1 E 0 VC Number 0
31 30 29 28 27 26 25 24 23 18 17 6 5 0
Tx_Ready command
VC Number The VC number of the channel which V R 4120A intends to start transmission.
Packet descriptor address Address of the packet descriptor.
Tx_Ready command indication
E Error bit. If detects an error (ex. Invalid VC number), sets this bit to a ‘1’. When V R 4120A
issues this command, this bit has to be a ‘0’.
VC Number The VC number of the channel which V R 4120A intends to start transmission.