NEC Network Controller uPD98502 - Manual (Page 286)

CHAPTER 5 ETHERNET CONTROLLER
286 Preliminary User’s Manual S15543EJ1V0UM
5.2.3 En_MACC2 (MAC Configuration Register 2)
Bits Field R/W Default Description
31:11 Reserved R/W 0 Reserved for future use. Write 0s.
10 MCRST R/W 0 MAC Control Block software reset:
Setting this bit to a ‘1’ forces MAC Control Block to a software reset
operation.
In order to complete the software reset state, this bit needs to be cleared.
9 RFRST R/W 0 Receive Function Block software reset:
Setting this bit to a ‘1’ forces the Receive Function Block to a software reset
operation. In order to complete the software reset, this bit needs to be
cleared.
8 TFRST R/W 0 Transmit Function Block software reset:
Setting this bit to a ‘1’ forces Transmit Function Block to a software reset
operation. In order to complete the software reset, this bit needs to be
cleared.
7 Reserved R/W 0 Reserved for future use. Write a 0.
6 BPNB R/W 0 Back Pressure No Back Off:
When this bit is set to a ‘1’, MAC Control Block transmits the packet with no
back off operation after the back pressure operation only.
5 APD R/W 0 Auto VLAN PAD:
When this bit is set to a ‘1’, if the ETPID field in the current transmit packet is
equal to the value in the En_VLTP register, MAC pads the current packet as
a VLAN packet when the current packet should be padded.
4 VPD R/W 0 VLAN PAD mode:
When this bit is set to a ‘1’, MAC Control Block always pads the current
packet as a VLAN packet when the current packet should be padded.
3:0 Reserved R/W 0 Reserved for future use. Write 0s.
5.2.4 En_IPGT (Back-to-Back IPG Register)
Bits Field R/W Default Description
31:7 Reserved R/W 0 Reserved for future use. Write 0s.
6:0 IPGT R/W 13H Back-to-Back IPG:
This field sets IPG for transmit operation with back-to-back mode.
The formula for the Back-to-Back IPG is:
IPG = (5 + IPGT) × 4 bits time
5.2.5 En_IPGR (Non Back-to-Back IPG Register)
Bits Field R/W Default Description
31:15 Reserved R/W 0 Reserved for future use. Write 0s.
14:8 IPGR1 R/W 0EH Carrier sense time:
This field sets the carrier sense time when the transmit operation is executed
in non Back-to-Back mode. The formula for the carrier sense time is:
Carrier sense time = (2 + IPGR1) × 4 bits time
The carrier sense time defined in this field is included in the non Back-to-
Back IPG defined in the IPGR2 field.
7 Reserved - - Reserved for future use. Write a 0.
6:0 IPGR2 R/W 13H Non Back-To-Back IPG:
This field sets IPG for transmit operation with non Back-to-Back mode. The
formula for the non Back-to-Back IPG is:
IPG = (5 + IPGR2) × 4 bits time