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STM32F101xx, STM32F102xx, STM32F103xx, STM32F105xx and ...

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Ethernet (ETH): media access control (MAC) with DMA controller<br />

RM0008<br />

Bit 3 RE: Receive error<br />

When set, this bit indicates that the RX_ERR signal is asserted while RX_DV is asserted during<br />

frame reception.<br />

Bit 2 DE: Dribble bit error<br />

When set, this bit indicates that the received frame has a non-integer multiple of bytes (odd<br />

nibbles). This bit is valid only in MII mode.<br />

Bit 1 CE: CRC error<br />

When set, this bit indicates that a cyclic redundancy check (CRC) error occurred on the<br />

received frame. This field is valid only when the last descriptor (RDES0[8]) is set.<br />

Bit 0 PCE: Payload checksum error<br />

When set, it indicates that the TCP, UDP or ICMP checksum the core calculated does not<br />

match the received encapsulated TCP, UDP or ICMP segment’s Checksum field. This bit is also<br />

set when the received number of payload bytes does not match the value indicated in the<br />

Length field of the encapsulated IPv4 or IPv6 datagram in the received Ethernet frame.<br />

Bits 5, 7, <strong>and</strong> 0 reflect the conditions discussed in Table 196.<br />

Table 196. Receive descriptor 0<br />

Bit 5:<br />

frame<br />

type<br />

Bit 7: IPC<br />

checksum<br />

error<br />

Bit 0: payload<br />

checksum<br />

error<br />

Frame status<br />

0 0 0<br />

IEEE 802.3 Type frame (Length field value is less than<br />

0x0600.)<br />

1 0 0 IPv4/IPv6 Type frame, no checksum error detected<br />

1 0 1<br />

1 1 0<br />

1 1 1<br />

0 0 1<br />

0 1 1<br />

0 1 0 Reserved<br />

IPv4/IPv6 Type frame with a payload checksum error (as described<br />

for PCE) detected<br />

IPv4/IPv6 Type frame with an IP header checksum error (as<br />

described for IPC CE) detected<br />

IPv4/IPv6 Type frame with both IP header <strong>and</strong> payload checksum<br />

errors detected<br />

IPv4/IPv6 Type frame with no IP header checksum error <strong>and</strong> the<br />

payload check bypassed, due to an unsupported payload<br />

A Type frame that is neither IPv4 or IPv6 (the checksum offload<br />

engine bypasses checksum completely.)<br />

900/995 Doc ID 13902 Rev 9

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