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CHAPTER 4 REGISTER DESCRIPTION
User’s Manual S14054EJ4V0UM
67
MACC2 - MAC configuration register 2 (register address A[7:0] = 01H) R/W
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
MCRST RFRST
TFRST Reserved
BPNB
APD
VPD
Reserved
Bit
Name
Function
Default
31:11
–
Reserved. Write 0 to these bits.
–
10
MCRST
MAC control block software reset.
When this bit is set to 1, software reset is executed.
To clear software reset, write 0 to this bit.
0
9
RFRST
Reception block software reset.
When this bit is set to 1, software reset is executed.
To clear software reset, write 0 to this bit.
0
8
TFRST
Transmission block software reset.
When this bit is set to 1, software reset is executed.
To clear software reset, write 0 to this bit.
0
7
–
Reserved. Write 0 to this bit.
–
6
BPNB
Back Pressure No Back Off.
When this bit is set to 1, only transmission after back pressure is not
backed off.
0
5
APD
Auto VLAN pad.
If this bit is set to 1, a transmit packet regarded as a VLAN packet is
processed based on MAX: 1522 bytes, MIN: 64 bytes. However, if this bit is
1 and if the PADEN bit of the MACC1 register is also 1, pad and CRC are
automatically appended to the transmit packets regarded as VLAN packets
that are less than 68 bytes, and packets are transmitted as 68 bytes.
The
µ
PD98431 regards the transmit packets matching the VLAN type
registered to the VLTP register as VLAN packets.
0
4
VPD
VLAN pad mode.
If this bit is set to 1, all transmit packets are regarded as VLAN packets and
processed based on MAX: 1522 bytes, MIN: 64 bytes. However, if this bit
is 1 and if the PADEN bit of the MACC1 register is also 1, pad and CRC
are automatically appended to these transmit packets that are less than 68
bytes, and packets are transmitted as 68 bytes.
Setting of the VPD bit takes precedence over setting of the APD bit.
0
3:0
–
Reserved. Write 0 to these bits.
–
Remark
When switching the settings of bits other than the software reset bits, be sure to execute software reset
after setting the registers. Refer to
3.16 (4) Cautions on switching settings of MACC1, MACC2,
MACC3, PCSC registers
.