STMicroelectronics STM32F405, Reference Manual

Page: 1179 / 1731

DocID018909 Rev 11 1179/1731
RM0090 Ethernet (ETH): media access control (MAC) with DMA controller
1232
Figure 383. Enhanced receive descriptor field format with IEEE1588 time stamp
enabled
• RDES4: Receive descriptor Word4
The extended status, shown below, is valid only when there is status related to IPv4
checksum or time stamp available as indicated by bit 0 in RDES0.
RDE S 3
O
W
N
S t a t us [ 3 0:0]
Re s erved
[ 3 0:29]
B u ffer 2 byte co u nt
[2 8 :16]
CTRL
[15:14]
B u ffer 1 byte co u nt
[12:0]
B u ffer 1 a ddre ss [ 3 1:0]
B u ffer 2 a ddre ss [ 3 1:0] or Next de s criptor a ddre ss [ 3 1:0]
RDE S 0
RDE S 1
RDE S 2
3 1 0
a i17104
Re s .
CT
RL
RDE S 7
RDE S 4
RDE S 5
RDE S 6
Extended S t a t us [ 3 1:0]
Re s erved
Time s t a mp low [ 3 1:0]
Time s t a mp high [ 3 1:0]
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
Reserved
PV
PFT
PMT
IPV
6
PR
IPV
4
PR
IP
CB
IPPE IP
HE
IPPT
rw rw rw rw rw rw rw rw rw rw rw rw rw rw
Bits 31:14 Reserved, must be kept at reset value.
Bit 13 PV: PTP version
When set, indicates that the received PTP message uses the IEEE 1588 version 2 format.
When cleared, it uses version 1 format. This is valid only if the message type is non-zero.
Bit 12 PFT: PTP frame type
When set, this bit indicates that the PTP message is sent directly over Ethernet. When this bit
is cleared and the message type is non-zero, it indicates that the PTP message is sent over
UDP-IPv4 or UDP-IPv6. The information on IPv4 or IPv6 can be obtained from bits 6 and 7.