749
/
838
Nations Technologies Inc.
Tel
:
+86-755-86309900
:
Address: Nations Tower, #109 Baoshen Road, Hi-tech Park North.
Nanshan District, Shenzhen, 518057, P.R.China
Bit field
Name
Description
14
FES
Ethernet speed selection.
0: 10Mbps
1: 100Mbps
13
DO
Disable self-receive function.
This bit has no meaning in full duplex mode.
0: MAC receives all packets from the PHY when transmitting.
1: MAC does not receive frames in half-duplex mode.
12
LM
Loopback mode.
0: MAC works in normal mode.
1: MAC works in Loopback mode (receive clock Rx_CLK input is required).
11
DM
Duplex mode selection.
0: Half-duplex mode.
1: Full duplex mode.
10
IPC
IP frame checksum.
0: Disable TCP/UDP/ICMP header checksum check of receiver.
1: Enable checksum check function of receiver.
9
DR
Disable retry.
This bit is only valid in half-duplex mode.
0: MAC will retransmit after a certain period of time according to the settings of these
bits in ETH_MACCFG.BL[1:0] after a collision.
1: MAC will only attempt to send 1 time. If a collision occurs on MII, MAC will
abort the transmission and report an excessive collision error in the transmit status
message.
8
Reserved
Reserved, the reset value must be maintained.
7
ACS
Automatic PAD/CRC stripping.
0: MAC will forward all received frames without changing the content of the frame.
1: MAC will remove PAD field and CRC field of frames less than or equal to 1536
bytes, and frames exceeding 1536 bytes will be forwarded directly.
6:5
BL[1:0]
Back off limit.
After a collision, MAC needs to delay for some time before retransmitting the current
frame. The time base unit of this delay time (dt) is called a time slot, and a time slot is
512 bits of time. This delay time (dt) is a random integer value calculated by: 0≤dt
<2
k
00
:
k = min(n, 10)
01
:
k = min(n, 8)
10
:
k = min(n, 4)
11
:
k = min(n, 1)
Where: n = number of retransmissions.
Note: These bits are only valid in half-duplex mode.
4
DC
Deferral inspection.
This bit is only valid in half-duplex mode.
0: Disable MAC deferral check function. MAC will delay sending until the CRS