91C100FDREVB Datasheet, PDF (39/68 Pages) SMSC Corporation – FEAST FAST ETHERNET CONTROLLER WITH FULL DUPLEX CAPABILITY

ISR
Save Bank Select & Address
Ptr Registers
Mask SMC91C100FD
Interrupts
Read Interrupt Register
No
Yes
RX INTR?
Yes
Call TX INTR or TXEMPTY
TX INTR?
INTR
No
Call RXINTR
Get Next TX
Packet
Available for
Yes ^{Transmission?}
No
Call ALLOCATE
ALLOC INTR?
No
Yes
Write Allocated Pkt # into
Packet Number Reg.
Write Ad Ptr Reg. & Copy Data
& Source Address
Yes
Call EPH INTR
EPH INTR?
No
Restore Address Pointer &
Bank Select Registers
Unmask SMC91C100FD
Interrupts
Exit ISR
Enqueue Packet
Set "Ready for Packet" Flag
Return Buffers to Upper Layer
Disable Allocation Interrupt
Mask
FIGURE 6 - INTERRUPT SERVICE ROUTINE
SMSC DS – LAN91C100FD REV. B
Page 39
Rev. 05/31/2000