LAN91C111 Datasheet, PDF (74/142 Pages) SMSC Corporation – 10/100 Non-PCI Ethernet Single Chip MAC + PHY

10/100 Non-PCI Ethernet Single Chip MAC + PHY
Datasheet
■ Clearing the LE ENABLE bit in the Control Register if an EPH interrupt is caused by a LINK_OK
transition.
■ Reading the Counter Register if an EPH interrupt is caused by statistics counter roll over.
■ Setting TXENA bit high if an EPH interrupt is caused by any of the fatal transmit error listed above
(3.1 to 3.5).
RX_OVRN INT - Set when 1) the receiver aborts due to an overrun due to a failed memory allocation,
2) the receiver aborts due to a packet length of greater than 2K bytes, or 3) the receiver aborts due
to the RCV DISCRD bit in the ERCV register set. The RX_OVRN INT bit latches the condition for the
purpose of being polled or generating an interrupt, and will only be cleared by writing the acknowledge
register with the RX_OVRN INT bit set.
ALLOC INT - Set when an MMU request for TX ram pages is successful. This bit is the complement
of the FAILED bit in the ALLOCATION RESULT register. The ALLOC INT bit is cleared by the MMU
when the next allocation request is processed or allocation fails.
TX EMPTY INT - Set if the TX FIFO goes empty, can be used to generate a single interrupt at the
end of a sequence of packets enqueued for transmission. This bit latches the empty condition, and
the bit will stay set until it is specifically cleared by writing the acknowledge register with the TX EMPTY
INT bit set. If a real time reading of the FIFO empty is desired, the bit should be first cleared and then
read.
The TX_EMPTY MASK bit should only be set after the following steps:
■ A packet is enqueued for transmission
■ The previous empty condition is cleared (acknowledged)
TX INT - Set when at least one packet transmission was completed or any of the below transmit fatal
errors occurs:
■ TXUNRN - Transmit under-run
■ SQET - SQE Error
■ LOST CARR - Lost Carrier
■ LATCOL - Late Collision
■ 16COL - 16 collisions
The first packet number to be serviced can be read from the FIFO PORTS register. The TX INT bit is
always the logic complement of the TEMPTY bit in the FIFO PORTS register. After servicing a packet
number, its TX INT interrupt is removed by writing the Interrupt Acknowledge Register with the TX INT
bit set.
RCV INT - Set when a receive interrupt is generated. The first packet number to be serviced can be
read from the FIFO PORTS register. The RCV INT bit is always the logic complement of the REMPTY
bit in the FIFO PORTS register.
Receive Interrupt is cleared when RX FIFO is empty.
Revision 1.8 (07-13-05)
74
DATASHEET
SMSC LAN91C111-REV B