Figure 30. transmit operation in polling mode, 8 completing transmission, Cs8900a – Cirrus Logic CS8900A User Manual
Page 103: Crystal lan™ ethernet controller
DS271F5
103
CS8900A
Crystal LAN™ Ethernet Controller
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5.6.8 Completing Transmission
When the CS8900A successfully completes
transmitting a frame, it sets the TxOK bit (Reg-
ister 8, TxEvent, Bit 8). If the TxOKiE bit (Reg-
ister 7, TxCFG, bit 8) is set, the CS8900A
generates a corresponding interrupt.
CS8900A Commits
Buffer Space to
Transmit Frame
Host Reads the BusST
Register (Register 18)
Transmit Request
Host Writes
Transmit Frame
to CS8900A
Host Writes Transmit Command
to the TxCMD Register
Host Writes Transmit Frame
Length to the TxLength Register
Exit Transmit Process
Yes
No
Enter Packet Transmit Process
Rdy4
TxNOW
bit = 1?
Polling Loop
No
Yes
Is
TxCMD
pending?
Exit: can't Issue command
Note: Issuing a command
at this point will cause
previous transmit frame
to be lost.
CS8900A
Transmits Frame
Figure 30. Transmit Operation in Polling Mode