LAN9221 Datasheet, PDF (63/151 Pages) SMSC Corporation – High-Performance 16-bit Non-PCI 10/100 Ethernet Controller with Variable Voltage I/O

High-Performance 16-bit Non-PCI 10/100 Ethernet Controller with Variable Voltage I/O
Datasheet
3.13.1 RX Slave PIO Operation
Using PIO mode, the host can either implement a polling or interrupt scheme to empty the received
packet out of the RX data FIFO. The host will remain in the idle state until it receives an indication
(interrupt or polling) that data is available in the RX data FIFO. The host will then read the RX status
FIFO to get the packet status, which will contain the packet length and any other status information.
The host should perform the proper number of reads, as indicated by the packet length plus the start
offset and the amount of optional padding added to the end of the frame, from the RX data FIFO.
init
Last Packet
Idle
RX Interrupt
Read RX
Status
DWORD
Read RX
Packet
Not Last Packet
Figure 3.18 Host Receive Routine Using Interrupts
SMSC LAN9221/LAN9221i
init
Last Packet
Read
RX_FIFO_
INf
Valid Status DWORD
Read RX
Status
DWORD
Read RX
Packet
Not Last Packet
Figure 3.19 Host Receive Routine with Polling
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DATASHEET
Revision 2.6 (12-04-08)