LAN91C94 Standard Microsystems, LAN91C94 Datasheet - Page 69

• Manufacturer Part Number: LAN91C94
• Manufacturer: Standard Microsystems

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