7-27
Register Descriptions
Ethernet Registers
The following registers are accessible from PCI configuration, memory, and direct I/O
space. They are all synchronized to the Ethernet Transmit clock.
General Ethernet Functional Registers
GeneralEthernetCtrl Register
Type: R/W
Internal Registers Subgroup: Ethernet Functional Registers
Byte Address: 70h - 73h
Table 7-39. GeneralEthernetCtrl Register
Bit(s)
rw
Reset
value
Description/Function
31:10
r
0
Reserved:
Always reads 0.
9
r/w
0
Reserved:
Always reads 0.
8
r/w
0
SetSoftInt:
When set, the S
OFT
I
NT
status bit in the
I
NTERRUPT
S
TATUS
register is set. This bit is always read as ‘0’.
7
r/w
0
Reserved:
Always reads 0.
6
r/w
0
Reserved:
Always reads 0.
5
r/w
0
TxGfpEn:
When set, the transmit general frame processor is
enabled, otherwise it remains in the reset state.
4
r/w
0
RxGfpEn:
When set, the receive general frame processor is enabled,
otherwise it remains in the reset state.
3
r/w
0
TxDmaEn:
Controls the transmit DMA operation. When the bit is
cleared the transmit module (data, buffer descriptors, completion
descriptors) does not issue any DMA requests. The bit is cleared by
the software driver, or when the PCI master encounters a PCI error
which should disable the DMA operation. Note that only when the
T
X
D
MA
E
N
bit is cleared can the software driver access and write the
transmit DMA buffer queue consumer index and the transmit DMA
completion queue producer index.
2
r/w
0
RxDmaEn:
Controls the receive DMA operation. When the bit is
cleared, the receive DMA module (data, buffer descriptors,
completion descriptors) does not issue any DMA requests. The bit is
cleared when the PCI master encounters a PCI error which should
disable the DMA operation. Note that only when the R
X
D
MA
E
N
bit
is cleared can the software driver access and write the receive DMA
buffer queue consumer index and the receive DMA completion
queue producer index.
1
r/w
0
TransmitEn:
Controls the transmit engine operation. When the bit is
cleared, no data is transmitted. This bit has no effect on the transmit
DMA operation.
0
r/w
0
ReceiveEn:
Controls the receive engine operation. When the bit is
cleared, all newly received frames are discarded. This bit has no
effect on the receive DMA operation.