7-46
AIC-6915 Ethernet LAN Controller Programmer’s Manual
CompletionQueueConsumerIndex
Type: R/W
Internal Registers Subgroup: Ethernet Functional Registers
Byte Address: C4h - C7h
Note:
A queue is considered empty if both Q
UEUE
P
RODUCER
I
NDEX
and
Q
UEUE
C
ONSUMER
I
NDEX
are equal. The queue is considered full if the value of
Q
UEUE
P
RODUCER
I
NDEX
+ 1 is equal to the value of Q
UEUE
C
ONSUMER
I
NDEX
.
If the corresponding C
OMPLETION
S
IZE
bit is cleared, the index points to a 4-byte
address. If the bit is set, it points to an 8-byte address..
Table 7-59. CompletionQueueConsumerIndex Register
Bit(s)
rw
Reset
Value
Description/Function
31
r/w
0
TxCompletionThresholdMode
: This bit indicates when
TxCompletionInt
is asserted. In the default state (‘0’) the interrupt
is asserted if the number of empty entries in the queue is less than or
equal to a programmable threshold. When the bit is set, the
interrupt status bit is asserted if the number of valid completion
descriptors in the queue is greater than or equal to the
programmable threshold.
30:26
r
0
Reserved:
Always read and write 0.
25:16
r/w
0
TxCompletionConsumerIndex:
Written by the software driver and
read by the AIC-6915. The software driver increments or writes a
new index to free space in the queue.
15
r/w
0
RxCompletionQ1ThresholdMode
: This bit indicates when
RxCompletionQueue1Int
is asserted. In the default state (‘0’) the
interrupt is asserted if the number of empty entries in the queue is
less than or equal to a programmable threshold. When the bit is set,
the interrupt status bit is asserted if the number of valid completion
descriptors in the queue is greater than or equal to the
programmable threshold.
14:10
r
0
Reserved:
Always read and write 0.
9:0
r/w
0
RxCompletionQ1ConsumerIndex:
Written by software driver and
read by the AIC-6915. The software driver increments or writes a
new index to free space in the queue.
