91C94 Datasheet, PDF (69/120 Pages) SMSC Corporation – ISA/PCMCIA SINGLE CHIP ETHERNET CONTROLLER WITH RAM

IS R
S ave Bank Sel ect & Addre ss
Ptr R egisters
Mas k 91C94 Interrupts
Read Interrup t Regist er
C all TX INTR or TXEMPTY
IN TR
Ge t N ext TX
No
Yes
RX INTR?
Yes
TX INTR?
No
Call RXINTR
Pac ket
Av ailable for
Yes ^{Tra ns mis sion?}
No
Call A LLOCATE
ALLOC INTR?
No
Yes
Write Allocated Pk t # into
Packet Number Reg.
Writ e Ad Ptr Reg. & Co py Data
& Sour ce Address
Yes
C all E PH INTR
EPH INTR?
No
R est or e Address Pointer &
Bank Selec t R egisters
U nmas k 91C94 I nterrupts
Ex it ISR
Enqueue Pac ket
Set "Ready for Packet" Flag
Return Buffers to Up per Lay er
Disa ble Allocation I nte rrupt
Mask
FIGURE 12 – INTERRUPT SERVICE ROUTINE
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