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CHAPTER 4 ATM CELL PROCESSOR
306
Preliminary User’s Manual S14767EJ1V0UM00
4.7.6
Tx_Ready command
The Tx_Ready command is used by the V
R
4120A RISC Processor to notify ATM Cell Processor that a transmit
packet has been added for a specified channel (a new packet descriptor has been added to the send 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 4-25. Tx_Ready Command and Tx_Ready Command Indication
0
1
1
0
Tx_Ready Command
0
PACKET DESCRIPTOR ADDRESS
CMR
CER
VC NUMBER
A/I
0
29
0
31 30
28 27 26 25 24
18 17
6
5
0
0
1
1
0
Tx_Ready Command Indication
0
CMR
VC NUMBER
A/I
0
29
0
31 30
28 27 26 25 24
18 17
6
5
0
E
23
Tx_Ready command
A/I
Indicates whether to send ATM mode packet or IPoA mode packet. In ATM mode, this bit is set
to 1.
The VC number of the channel which V
R
IPoA mode, this field is invalid and has to be set to 0.
Address of the packet descriptor.
VC NUMBER
Packet
address
descriptor
Tx_Ready command indication
A/I
Indicates whether to send ATM mode packet or IPoA mode packet. In ATM mode, this bit is set
to 1.
Error bit. If detects an error, sets this bit to 1. When V
R
4120A RISC Processor issues this
command, this bit has to be 0.The possible errors are:
VC number is invalid.
PacketInfo structure cannot be obtained.
The flow is used in different transmission mode.
The VC number of the channel which V
R
4120A RISC Processor intends to start transmission.
E
VC NUMBER