
RTL8100B(L) 
2001-11-9 
Rev.1.41 
14 
5.3 ERSR: Early Rx Status Register  
(Offset 0036h, R) 
Bit
7-4 
3 
R/W
- 
R 
Symbol
- 
ERGood 
Description 
Reserved 
Early Rx Good packet:
 This bit is set whenever a packet is completely 
received and the packet is good. Writing a 1 to this bit will clear it. 
Early Rx Bad packet:
 This bit is set whenever a packet is completely 
received and the packet is bad. Writing a 1 to this bit will clear it. 
Early Rx OverWrite:
 This bit is set when the RTL8100B(L)'s local 
address pointer is equal to CAPR. In the early mode, this is different 
from buffer overflow. It happens that the RTL8100B(L) detected an Rx 
error and wanted to fill another packet data from the beginning address 
of that error packet. Writing a 1 to this bit will clear it. 
Early Rx OK:
 The power-on value is 0. It is set when the Rx byte count 
of the arriving packet exceeds the Rx threshold. After the whole packet 
is received, the RTL8100B(L) will set ROK or RER in ISR and clear 
this bit simultaneously. Setting this bit will invoke a ROK interrupt. 
2 
R 
ERBad 
1 
R 
EROVW 
0 
R 
EROK 
5.4 Command Register  
(Offset 0037h, R/W) 
This register is used for issuing commands to the RTL8100B(L). These commands are issued by setting the corresponding bits for the 
function. A global software reset along with individual reset and enable/disable for transmitter and receiver are provided here. 
Bit
7-5 
4 
R/W
- 
R/W 
Symbol
- 
RST 
Description
Reserved 
Reset:
 Setting to 1 forces the RTL8100B(L) to a software reset state 
which disables the transmitter and receiver, reinitializes the FIFOs, 
resets the system buffer pointer to the initial value (Tx buffer is at 
TSAD0, Rx buffer is empty). The values of IDR0-5 and MAR0-7 and 
PCI configuration space will have no changes. This bit is 1 during the 
reset operation, and is cleared to 0 by the RTL8100B(L) when the reset 
operation is complete. 
Receiver Enable: 
When set to 1, and the receive state machine is idle, 
the receive machine becomes active. This bit will read back as a 1 
whenever the receive state machine is active. After initial power-up, 
software must insure that the receiver has completely reset before 
setting this bit. This bit will be reset after PCI reset deassertion. 
Transmitter Enable: 
When set to 1, and the transmit state machine is 
idle, then the transmit state machine becomes active. This bit will read 
back as a 1 whenever the transmit state machine is active. After initial 
power-up, software must insure that the transmitter has completely reset 
before setting this bit. This bit will be reset after PCI reset deassertion.
Reserved 
Buffer Empty:
 Rx Buffer Empty. There is no packet stored in the Rx 
buffer ring. 
3 
R/W 
RE 
2 
R/W 
TE 
1 
0 
- 
R 
- 
BUFE