NS7520B-1-I46 Digi International, NS7520B-1-I46 Datasheet - Page 191

• Manufacturer Part Number: NS7520B-1-I46
• Description: IC ARM MICROPROCESSOR 177BGA
• Manufacturer: Digi International
• Series: NET+ARM®r

Specifications of NS7520B-1-I46

• Applications: Network Processor
• Core Processor: ARM7
• Program Memory Type: External Program Memory
• Controller Series: -
• Ram Size: External
• Interface: EBI/EMI, Ethernet, DMA, SPI, UART
• Number Of I /o: 16
• Voltage - Supply: 1.4 V ~ 3.6 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 177-LFBGA
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

Register bit assignment
Table 61: MAC Configuration Register 2 bit definition
D31:15
D14
D13
D12
D11:10
D09
D08
Bits
N/A
R/W
R/W
R/W
N/A
R/W
R/W
Access
Reserved
EDEFER
BACKP
NOBO
Reserved
LONGP
PUREP
Mnemonic
N/A
0
0
0
N/A
0
0
Reset
N/A
Excess Deferral
1
0
Backpressure/NO back off
0
1
No back off
When this bit is set to 1, the MAC immediately retransmits
after a collision, rather than using the binary exponential
back off algorithm defined in the 802.3u standard.
N/A
Long preamble enforcement
1
0
Pure preamble enforcement
1
0
Description
w w w . d i g i e m b e d d e d . c o m
Allows the MAC to defer to carrier indefinitely, per
the 802.3u standard.
The MAC aborts when the excessive deferral limit is
reached. The MAC provides feedback to the host
system (through a transmit abort condition defined in
the Transmit Status register (see "TXAED" on page
170).
After a collision, the MAC waits a random amount of
time to retransmit packets (“back off”).
After a collision, the MAC immediately retransmits
packets without backoff. This reduces the chance of
further collisions and ensures that transmit packets are
sent.
The MAC allows only those receive packets that
contain preamble fields less than 12 bytes in length.
The MAC allows any length preamble, as defined in
the 802.3u standard.
The MAC verifies the preamble‘s content to ensure it
contains
the preamble is discarded.
There is no preamble checking.
’h55
and is error-free. A packet with errors in
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