ST STM32F101xx User Manual

RM0008 Ethernet (ETH): media access control (MAC) with DMA controller
Doc ID 13902 Rev 12 953/1096
Figure 335. MAC frame format
Figure 336. Tagged MAC frame format
Each byte of the MAC frame, except the FCS field, is transmitted low-order bit first.
An invalid MAC frame is defined by one of the following conditions:
● The frame length is inconsistent with the expected value as specified by the length/type
field. If the length/type field contains a type value, then the frame length is assumed to
be consistent with this field (no invalid frame)
● The frame length is not an integer number of bytes (extra bits)
● The CRC value computed on the incoming frame does not match the included FCS
Preamble
SFD
Destination address
Source address
MAC client length/type
MAC client data
PAD
Frame check sequence
7 bytes
1 byte
6 bytes
6 bytes
2 bytes
46-1500 bytes
4 bytes
MSB LSB
Bit transmission order (right to left)
Bytes within
frame transmitted
top to bottom
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Preamble
SFD
Destination address
Source address
Length/type = 802.1QTagType
Tag control information
MAC client length/type
MAC client data
7 bytes
1 byte
6 bytes
6 bytes
QTag Prefix
42-1500 bytes
2 bytes
MSB LSB
Bit transmission order (right to left)
bytes within
frame transmitted
top to bottom
Frame check sequence
Pad
4 bytes
4 bytes
1 0 0 0 0 0 0 0 1
VLAN identifier (VID, 12 bits)
CFIUser priority
MSB LSB
0 0 0 0 0 0 0 0 0
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ST STM32F101xx Specifications

General

Brand	ST
Model	STM32F101xx
Category	Microcontrollers
Language	English