CS8900-CQ3 Cirrus Logic, CS8900-CQ3 Datasheet - Page 104

• Manufacturer Part Number: CS8900-CQ3
• Description: Crystal LAN ISA Ethernet Controller
• Manufacturer: Cirrus Logic

Or:
104
any yet-to-be-transmitted frames queued in the
on-chip memory, are cleared and not transmit-
ted. The host should make TxLength = 0 when
using the Force bit.
Process other events
that caused interrupt
Host Enters Interrupt Routine
No
Host Reads
Exit: can’t Issue command
Note: Issuing a command
at this point will cause
previous transmit frame
to be lost.
Rdy4Tx
bit = 1?
ISQ
CIRRUS LOGIC PRODUCT DATA SHEET
Figure 31. Transmit Operation in Interrupt Mode
Yes
Host Writes Transmit Command
Enter Packet Transmit Process
Length to the TxLength Register
Yes
Host Writes Transmit Frame
Exit Transmit Process
CS8900A Commits
to the TxCMD Register
Exit WAIT-for-interrupt
Host Reads the BusST
Register (Register 18)
Transmits Frame
Transmit Frame
Buffer Space to
Transmit Frame
to CS8900A
Host Writes
CS8900A
pending?
No
TxCMD
TxNOW
No
bit = 1?
3) There is a transmit under-run, and the Tx-
Successful transmission is indicated when the
TxOK bit (Register 8, TxEvent, Bit 8) is set.
Rdy4
Is
Underrun bit (Register C, BufEvent, Bit 9) is
set.
Yes
Crystal LAN™ ISA Ethernet Controller
Transmit Request
CS8900A
DS271PP3