NEC Network Controller uPD98502 - Manual (Page 304)

CHAPTER 5 ETHERNET CONTROLLER
304 Preliminary User’s Manual S15543EJ1V0UM
Figure 5-7. Transmit Procedure
V
R
4120A Ethernet Controller External PHY Device
Initialize Registers Initialize
Auto Negotiation Link Configuration
Prepare
Buffer Descriptors
and
Transmit Data
mem
Set
Transmit Descriptor
address
Set XMDP
Set Transmit Enable
Set TXE
Get transmit data
Exceed TXDRTH
Send
Preamble/SFD
and
Data, FCS
mem
Write TX_Status
and
Read next Descriptor/data
Generate interrupt
(Transmit done)
Interrupt
Carrier Sense
Status Check
and
Preparation for
next data
Carrier Sense
Encode/Scramble