AM79C978A AMD [Advanced Micro Devices], AM79C978A Datasheet - Page 120

• Manufacturer Part Number: AM79C978A
• Description: Single-Chip 1/10 Mbps PCI Home Networking Controller
• Manufacturer: AMD [Advanced Micro Devices]

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RES
RDMD
SRAM (if one is enabled) will be
transmitted and all receive pack-
ets stored in the receive FIFOs,
and the receive buffer area in the
SRAM (if one is enabled) will be
transferred into system memory.
Since the FIFO and SRAM con-
tents are flushed, it may take
much
Am79C978A controller enters the
suspend mode. The amount of
time that it takes depends on
many factors including the size of
the SRAM, bus latency, and net-
work traffic level.
When a write to CSR5 is per-
formed with bit 0 (SPND) set to 1,
the value that is simultaneously
written to FASTSPNDE is used to
determine which approach is
used to enter suspend mode.
This bit is always read/write ac-
cessible. FASTSPNDE is cleared
by H_RESET, S_RESET, or by
setting the STOP bit.
RDMD is required to be set if the
RXDPOLL bit in CSR7 is set. Set-
ting RDMD while RXDPOLL = 0
merely hastens the Am79C978A
controller’s response to a receive
Descriptor Ring Entry.
This bit is always read/write ac-
cessible. RDMD is set by writing
a 1. Writing a 0 has no effect.
RDMD will be cleared by the Buff-
er Management Unit when it
fetches a receive Descriptor.
RDMD is cleared by H_RESET.
RDMD
S_RESET or by setting the
STOP bit.
Reserved location.
Receive Demand, when set,
causes the Buffer Management
Unit to access the Receive De-
scriptor Ring without waiting for
the receive poll-time counter to
elapse. If RXON is not enabled,
RDMD has no meaning and no
receive Descriptor Ring access
will occur.
longer
is
unaffected
before
Am79C978A
the
by
12
11
10
9
RXDPOLL
STINT
STINTE
MREINT
RXDPOLL is set, the Buffer Man-
agement Unit will disable receive
polling. Likewise, if RXDPOLL is
cleared, automatic receive poll-
ing is enabled. If RXDPOLL is
set, RDMD bit in CSR7 must be
set in order to initiate a manual
poll of a receive descriptor. Re-
ceive Descriptor Polling will not
take place if RXON is reset.
This bit is always read/write ac-
cessible. RXDPOLL is cleared by
H_RESET. RXDPOLL is unaf-
fected by S_RESET or by setting
the STOP bit.
Software Timer interrupt is set by
the Am79C978A controller when
the Software Timer counts down
to 0. The Software Timer will im-
mediately load the STVAL (BCR
31, bits 5-0) into the Software
Timer and begin counting down.
When STINT is set to 1, INTA is
asserted if the enable bit STINTE
is set to 1.
This bit is always read/write ac-
cessible. STINT is cleared by
the host by writing a 1. Writing a
0 has no effect. STINT is
cleared by H_RESET and is not
affected by S_RESET or setting
the STOP bit.
If STINTE is set, the STINT bit
will be able to set the INTR bit.
This bit is always read/write ac-
cessible. STINTE is set to 0 by
H_RESET and is not affected by
S_RESET or setting the STOP bit
terrupt. The PHY Read Error in-
terrupt is set by the Am79C978A
controller to indicate that the cur-
rently read register from the PHY
is invalid, the contents of BCR34
are incorrect, and the operation
should be performed again. The
indication of an incorrect read
comes from the internal PHY.
Receive
Software Timer Interrupt. The
Software Timer Interrupt Enable.
PHY Management Read Error In-
Disable
Polling.
If