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Nations Technologies Inc.
Tel
:
+86-755-86309900
:
Address: Nations Tower, #109 Baoshen Road, Hi-tech Park North.
Nanshan District, Shenzhen, 518057, P.R.China
–
The received frame length is less than the length indicated by IPv4 header length field, or IPv4/IPv6 header is
less than 20 bytes
The receiving checksum module can determine whether the data type of the IP packet is TCP, UDP or ICMP, and
calculate their checksum according to their respective specifications, including the data of TCP/UDP/ICMPv6
pseudo-header.
RDES0.RMAPCE is set to 1 when the received IP packet:
–
The calculated TCP, UDP or ICMP checksum does not match the value of the checksum field of its frame
–
The received TCP, UDP or ICMP data length does not match the length indicated by IP header
The receive checksum module does not calculate if IP packet is incomplete or with security features, IPv6 routing
headers, and data types other than TCP, UDP, or ICMP.
MAC loopback mode
Loopback mode is disabled by default, which is generally used for application testing and debugging of system
hardware and software. Set ETH_MACCFG.LM to 1 to enter MAC loopback mode, and MAC will transmit data by
itself and receive it by itself, that is, the sender transmit the frame to its own receiver.
MAC management counter (MMC)
MMC is a management counting unit that uses a set of registers to count the sent and received frames. See Section
25.5.22 ~ Section 25.5.32 for the specific function of each register and the address of each statistic counter. These
addresses can be used to read/write access to the required transmit/receive counters.
If there is no frame underflow, no carrier, carrier loss, excessive deferral, late collision, excessive collision, or Jabber
timeout error in the transmitted frame, it is considered that the transmission process is normal, and MMC transmission
counter will be automatically updated.
If the received frame is not aligned, CRC calculation result is inconsistent with the FCS value, the frame length is
less than 64 bytes, the value of the length field does not match the actual number of bytes received, exceeds the range,
and the MII_Rx_ER input is incorrect, the receiving process is considered normal. MMC receive counter is
automatically updated. In addition, if the destination address is not received completely and the length of the
discarded frame is less than 6 bytes, MMC reception counter will also be updated.
Note: The maximum range is 1518 bytes for basic frame and 1522 bytes for tagged frame (VLAN frames) (both with
preamble and SFD stripped).
25.4.7
Power management (PMT)
Ethernet module supports two methods to wake up the system from low power mode: Remote Wakeup Frame and
Magic Packet Wakeup Frame. To reduce power consumption, the host system and Ethernet module can be put into a
low-power state and listen for wake-up frames. If ETH_MACPMTCTRLSTS.PWRDWN is set to 1, Ethernet module
will enter a low-power state, and MAC will discard all frames until it receives a remote wake-up frame or a Magic
Packet wake-up frame to exit the low-power state. Set ETH_MACPMTCTRLSTS.RWKPKTEN to 1 to wake up the
Ethernet module when a remote wake-up frame is received; set ETH_MACPMTCTRLSTS.MGKPKTEN to 1 to
wake up the Ethernet module when a Magic Packet wake-up frame is received. Any wake-up function is enabled, as
long as MAC receives the corresponding wake-up frame, Ethernet module will generate a wake-up interrupt and exit