AX88140A Ver la hoja de datos (PDF) - Unspecified
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AX88140A Datasheet PDF : 46 Pages
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AX88140A
3
R/W/C
2
R/W/C
1
R/W/C
0
R/W/C
PRELIMINARY
TJT - Transmit Jabber Time-out
Indicates that the transmit jabber timer expired, meaning that the AX88140A transmitter had
been excessively active. The transmission process is aborted and placed in the stopped state.
This event causes the transmit jabber time-out TDES0<14> is set.
TU - Transmit Buffer Unavailable
Indicates that the next descriptor on the transmit list is owned by the host and cannot be acquired
by the AX88140A.The transmission process is suspended. To resume processing transmit
descriptors, the host should change the ownership bit of the descriptor and then issue a transmit
poll demand command.
TPS - Transmit Process Stopped
Asserts when the transmit process enters the stopped state.
TI - Transmit Interrupt
Indicates that a frame transmission was completed, while TDES1<31> is asserted in the first
descriptor of the frame.
Tab - 20 REG5 Status Register Description
4.2.7 Operation Mode Register (REG6)
1. REG6 establishes the receive and transmit operating modes and commands.
2. REG6 should be the last REG to be written as part of initialization.
Field
31
30
29:25
24
23
22
21
20
19
18
17:16
15:14
13
12
11:10
9
R/W/C
Description
- Reserved
R/W RA - Receive All
1 All incoming packets will be received
0 Filtering mode
- Reserved.--Written as “0” for future compatibility concern.
R/W SCR - Scrambler Mode
1 Enable Scrambler
R/W PCS - PCS Mode
0 Disable Scrambler
1 PCS functions are active
0 MII/SYM port is not selected
R/W TTM - Transmit Threshold Mode
1 Threshold is 10Mb/s
0 Threshold is 100Mb/s
R/W SF - Store and Forward
1 Enable Store and Forward
0 Disable Store and Forward
- Reserved.--Written as “0” for future compatibility concern.
R/W HBD - Heartbeat Disable
1 Heartbeat Disable
0 Heartbeat Enable
R/W PS - Port Select
1 MII/SYM port is selected.
0 SRL port is selected
- Reserved.--Written as “0” for future compatibility concern.
R/W TR - Threshold Control Bits
The threshold value has a direct impact on the AX88140A bus arbitration scheme . Transmission starts when
the frame size within the transmit FIFO is larger than the threshold. In addition, full frames with a length
less than the threshold are also transmitted. The transmit process must be in the stopped state to change these
bits.
Controls the selected threshold level for the AX88140A transmit FIFO. Four threshold levels are allowed.
REG6<18>=0
REG6<18>=1
REG6<18>=1
REG6<21>
0
REG6<15:14> REG6<22>=X
00
72
REG6<22>=1
72
REG6<22>=0
128
0
01
96
96
256
0
10
128
128
512
0
11
160
160
1024
1
XX
Store & Forward Store & Forward Store & Forward
R/W ST - Start/Stop Transmission
R/W FC - Force Collision Mode
R/W OM - Operating Mode
R/W FD - Full-Duplex Mode
1 Start Transmission
0 Stop Transmission
1 Enable force collision
0 Disable force collision
00 Normal
01 Internal Loop-back
10 External Loop-back
1 Full-Duplex
24
ASIX ELECTRONICS CORPORATION
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