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BIT
7
6
5
4
3
2
1
0
ERWCNT
RESET
0
0
0
0
0
0
0
0
ERW11
ERW10
ERW9
ERW8
ERW7
ERW6
ERW5
ERW4
5.2.12 GROUP0-GROUP7 - Multicast Filter
Table Registers
GROUP
Register
Normal Map
Port Address
Read
1:18
1:19
1:1A
1:1B
1:1C
1:1D
1:1E
1:1F
Linked-List Map
Port Address
Read
1:18
1:19
1:1A
1:1B
1:1C
1:1D
1:1E
1:1F
Write
1:18
1:19
1:1A
1:1B
1:1C
1:1D
1:1E
1:1F
Write
1:18
1:19
1:1A
1:1B
1:1C
1:1D
1:1E
1:1F
GROUP0
GROUP1
GROUP2
GROUP3
GROUP4
GROUP5
GROUP6
GROUP7
These 8 registers hold the node’s Multicast filter
table. See Table 5-10 for the registers’ bit
assignments.
5.2.13 INTMASK - Interrupt Mask Register
Normal Map Read Port = 2:1F Normal Map Write
Port = 0:1F
Linked-List Map Read Port = 2:1F Linked-List
Write Port = 0:1F
The Interrupt Mask Register is used to mask out
certain interrupt sources selectively. Mask bits set
to ’1’ allow the corresponding interrupts to cause an
IRQ. Mask bits set to ’0’ block their respective
interrupt sources.
BIT
7
6
5
4
3
2
1
0
INTMASK
RESET
0
0
0
0
0
0
0
0
—
ERWE
CNTE
OVWE
TXEE
RXEE
PTXE
PRXE
Bit 6: ERWE
, Early Receive Warning Enable
When ERWE = 1, this bit enables Early Receive
Warning as defined by the ERW bit in the Interrupt
Status Register. (See the next register, INTSTAT.)
Bit 5: CNTE
, Counter Overflow Enable
When CNTE = 1, this bit enables Counter Overflow
as defined by the CNT bit in the Interrupt Status
Register. (See the next register, INTSTAT.)
Bit 4: OVWE
, Overwrite Warning Enable
When OVWE = 1, this bit enables Overwrite Warn-
ing as defined by the OVW bit in the Interrupt Status
Register. (See the next register, INTSTAT.)
GROUP
Registers
GROUP0
GROUP1
GROUP2
GROUP3
GROUP4
GROUP5
GROUP6
GROUP7
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
BIT 0
GA07
GA15
GA23
GA31
GA39
GA47
GA55
GA63
GA06
GA14
GA22
GA30
GA38
GA46
GA54
GA62
GA05
GA13
GA21
GA29
GA37
GA45
GA53
GA61
GA04
GA12
GA20
GA28
GA36
GA44
GA52
GA60
GA03
GA11
GA19
GA27
GA35
GA43
GA51
GA59
GA02
GA10
GA18
GA26
GA34
GA42
GA50
GA58
GA01
GA09
GA17
GA25
GA33
GA41
GA49
GA57
GA00
GA08
GA16
GA24
GA32
GA40
GA48
GA56
TABLE 5-10. GROUP REGISTER BITS
ETHERNET SYSTEM CONTROLLER REGISTERS
83C795
27