![Geehy SEMICONDUCTOR APM32F405 Series Скачать руководство пользователя страница 569](http://html1.mh-extra.com/html/geehy-semiconductor/apm32f405-series/apm32f405-series_user-manual_573630569.webp)
www.geehy.com Page 568
Field
Name
R/W
Description
31
OWN
R/W
Own
0: This describer belongs to CPU
1: This describer belongs to DMA
This bit will be cleared when DMA completes frame receiving or the
allocated buffer in the descriptor is full.
Table 149 Configuration in Normal Descriptor Format
Bit 0
(PERRC_ESA)
Bit 5
(FT)
Bit 7
(IPCERR_TSV)
Frame state
0
0
0
IEEE 802.3 type frame
1
0
1
Type frame which is neither IPv4 nor IPv6
0
1
0
IPv4/IPv6 type frame; checksum error is not
detected
1
1
0
IPv4/IPv6 type frame; payload checksum error
is detected
0
1
1
IPv4/IPv6 type frame; IP header checksum
error is detected
1
1
1
IPv4/IPv6 type frame; IP header and payload
checksum error are detected
1
0
0
IPv4/IPv6 type frame; there is no IP header
checksum error, and the payload check
bypasses because the payload is not supported
0
0
1
Reserved
Receive descriptor word 1 (RXDES1)
Field
Name
R/W
Description
12:0
RXBS1
R/W
Receive Buffer 1 Size
0: DMA will ignore this buffer and use the buffer 2 or the next
descriptor according to the value of RXCH bit.
Other: It indicates the size of the first data buffer. The buffer size
must be a multiple of 4, 8, or 16, depending on the bus width, even if
the value of the buffer 2 address pointer is not aligned. When the
buffer size is not a multiple of 4, 8, or 16, the generated behavior is
undefined.
13
Reserved
14
RXCH
R/W
Second Address Chained
When this bit is set, the second address in the descriptor is the
address of the next descriptor, not the address of the second buffer.
Ignore the value of RXBS2. RXER has priority over RXCH.
15
RXER
R/W
Receive End of Ring
When this bit is set, it indicates that the descriptor list has reached
the final descriptor. DMA will return the base address of the
descriptor list and create a descriptor ring.