
RTL8100B(L) 
2001-11-9 
Rev.1.41 
17 
7-4 
R/W 
TXRR 
Tx Retry Count:
 These are used to specify additional transmission 
retries in multiple of 16 (IEEE 802.3 CSMA/CD retry count). If the 
TXRR is set to 0, the transmitter will re-transmit 16 times before 
aborting due to excessive collisions. If the TXRR is set to a value 
greater than 0, the transmitter will re-transmit a number of times equals 
to the following formula before aborting: 
Total retries = 16 + (TXRR * 16) 
The TER bit in the ISR register or transmit descriptor will be set when 
the transmission fails and reaches to this specified retry count. 
Reserved 
Clear Abort:
 Setting this bit to 1 causes the RTL8100B(L) to 
retransmit the packet at the last transmitted descriptor when this 
transmission was aborted, Setting this bit is only permitted in the 
transmit abort state.  
3-1 
0 
- 
- 
W 
CLRABT 
5.8 Receive Configuration Register  
(Offset 0044h-0047h, R/W) 
This register is used to set the receive configuration for the RTL8100B(L). Receive properties such as accepting error packets, 
runt packets, setting the receive drain threshold etc. are controlled here. 
Bit
31-28 
27-24 
R/W
- 
R/W 
Symbol
- 
ERTH3, 2, 1, 0 
Description
Reserved 
Early Rx threshold bits:
 These bits are used to select the Rx threshold 
multiplier of the whole packet that has been transferred to the system 
buffer in early mode when the frame protocol is under the 
RTL8100B(L)'s definition. 
0000 = no early Rx threshold 
0010 = 2/16 
0100 = 4/16 
0110 = 6/16 
1000 = 8/16 
1010 = 10/16 
1100 = 12/16 
1110 = 14/16 
Reserved 
Multiple early interrupt select: 
When this bit is set, any received 
packet invokes early interrupt according to MULINT<MISR[11:0]> 
setting in early mode. When this bit is reset, the packets of familiar 
protocols (IPX, IP, NDIS, etc) invoke early interrupt according to 
RCR<ERTH[3:0]> setting in early mode. The packets of unfamiliar 
protocols will invoke early interrupt according to the setting of 
MULINT<MISR[11:0]>. 
The RTL8100B(L) receives the error packet whose length is larger than 
8 bytes after setting the RER8 bit to 1. 
 The RTL8100B(L) receives the error packet larger than 64-byte long 
when the RER8 bit is cleared. The power-on default is zero.  
 If AER or AR is set, the RER will be set when the RTL8100B(L) 
receives an error packet whose length is larger than 8 bytes. The RER8 
is “ Don’t care “ in this situation. 
0001 = 1/16 
0011 = 3/16 
0101 = 5/16 
0111 = 7/16 
1001 = 9/16 
1011 = 11/16 
1101 = 13/16 
1111 = 15/16 
23-18 
17 
- 
- 
R/W 
MulERINT 
16 
R/W 
RER8