SMC Networks SMC91C95 User Manual
Page 53
53
I/O SPACE - BANK1
OFFSET
NAME
TYPE
SYMBOL
C
CONTROL REGISTER
READ/WRITE
CTR
HIGH
BYTE
0
RCV_
BAD
PWRDWN WAKEU
P_EN
AUTO
RELEASE
1
0
0
0
0
0
X
X
1
LOW
BYTE
LE
ENABLE
CR
ENABLE
TE
ENABLE
EEPROM
SELECT
RELOAD STORE
0
0
0
X
X
0
0
0
RCV_BAD - When set, bad CRC packets are
received. When clear bad CRC packets do not
generate interrupts and their memory is released.
PWRDN - Active high bit used to put the Ethernet
function in powerdown mode.
Cleared by:
1. A write to any register in the SMC91C95 I/O
space
2. Hardware reset
3. “Magic Packet” was received
This bit is combined with the Pwrdwn bit in ECSR
and with the powerdown bit to determine when the
function is powered down.
WAKUP_EN - Active high bit used to enable the
controller in any of the powerdown modes to power
up if a “Magic Packet” is detected and set the
WAKEUP bit in the EPHSR to generate an EPH
interrupt (if not masked). When clear (0), no
“Magic Packet” scanning is done on receive
packets.
NOTE:
If “Magic Packet” is enabled using this
bit only the notification is done on the WAKEUP bit
in the EPHSR only.
AUTO RELEASE - When set, transmit pages are
released by transmit completion if the transmission
was successful (when TX_SUC is set). In that
case there is no status word associated with its
packet number, and successful packet numbers
are not even written into the TX COMPLETION
FIFO. A sequence of transmit packets will only
generate an interrupt when the sequence is
completely transmitted (TX EMPTY INT will be
set), or when a packet in the sequence
experiences a fatal error (TX INT will be set).
Upon a fatal error TXENA is cleared and the
transmission sequence stops. The packet number
that failed is the present in the FIFO PORTS
register, and its pages are not released, allowing
the CPU to restart the sequence after corrective
action is taken.
LE ENABLE - Link Error Enable. When set it
enables the LINK_OK bit transition as one of the
interrupts merged into the EPH INT bit. Defaults
low (disabled). Writing this bit also serves as the
acknowledge by clearing previous LINK interrupt
conditions.