NEC Network Controller uPD98502 - Manual (Page 306)

CHAPTER 5 ETHERNET CONTROLLER
306 Preliminary User’s Manual S15543EJ1V0UM
When the receive frame is complete, Ethernet Controller sets the L-bit in the Receive Descriptor, writes the frame
status bits into the Receive Descriptor, and sets the OWN-bit. Ethernet Controller generates a maskable interrupt,
indicating that a frame has been received and is in memory. Ethernet Controller then waits for a new frame.
Receive procedure is as follows: (Figure 5-8)
Figure 5-8. Receive Procedure
V R 4120A Ethernet Controller External PHY Device
Initialize Registers Initialize
Auto Negotiation Link Configuration
Prepare
Buffer Descriptors
mem
Set
Receive Descriptor
address
Set Receive Enable
Set RCVDP
Set RXE
Decode/Descramble Exceed RXDRTH
Transfer
Receive Data
mem
If data buffer is full,
get next descriptor
Write RX_Status
and
Read next Descriptor
Generate interrupt
(Receive Done)
mem
Interrupt
Status Check
and
Data Read
End of Frame