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AT32F435/437
Series Reference Manual
2022.11.11
Page 626
Rev 2.03
This bit indicates that the frame to be transmitted was fully
sent to the MTL Tx FIFO.
Bit 9
RWT
0x0
rw1c
Receive Watchdog Timeout
When this bit is set, it indicates that the receive watchdog
timer timeout occurs while receiving the current frame, and
the current frame is cut off after the watchdog timeout
happens.
Bit 8
RPS
0x0
rw1c
Receive Process Stopped
This bit is set when the receive process enters the stop
state.
Bit 7
RBU
0x0
rw1c
Receive Buffer Unavailable
This bit indicates that the next descriptor in the receive list
is owned by the host and cannot be acquired by the DMA.
Thus the receive process is suspended. The host should
change the ownership of the descriptor and release the
receive poll demand command in order to resume receive
process. If no receive poll demand command is issued, the
receive process resumes when the DMA receives the next
incoming frame. This bit is set only when the previous
receive descriptor is owned by the DMA.
Bit 6
RI
0x0
rw1c
Receive Interrupt
This bit indicates the completion of a frame reception. After
the completion of a frame reception, the bit 31 of the
RDES1 (interrupt disabled after reset operation) is reset in
the last descriptor. Specific frame status information will be
posted in the descriptor. Receive process remains in the
running state.
Bit 5
UNF
0x0
rw1c
Transmit Underflow
This bit indicates that the transmit buffer has an underflow
during a frame transmission. Transmit process is
suspended and the underflow error bit TDES0[1] is set.
Bit 4
OVF
0x0
rw1c
Receive Overflow
This bit indicates that the receive buffer has an overflow
during a frame reception. If the partial frame has been
transferred to the application, the overflow status is set in
the RDES0[11].
Bit 3
TJT
0x0
rw1c
Transmit Jabber Timeout
This bit indicates that the transmit Jabber timer will expire
when the current frame is greater than 2047 bytes (it is
10240 bytes if Jumbo frame is enabled).
After the Jabber is expired, the transmit process is aborted
and enters stop state, which causes the transmit Jabber
timeout flag bit TDES0[14] to be set.
Bit 2
TBU
0x0
rw1c
Transmit Buffer Unavailable
This bit indicates that the next descriptor in the transmit list
is owned by the host and cannot be acquired by the DMA.
Then the transmit process is suspended. Bit [22: 20]
explains the transmit process state. To resume transmit
process, the host should change the ownership of the
descriptor by setting the TDES0[31] and issue the transmit
poll demand command
Bit 1
TPS
0x0
rw1c
Transmit Process Stopped
This bit is set when the transmit process stops.
Bit 0
TI
0x0
rw1c
Transmit Interrupt
This bit indicates the completion of a frame transmission.
The bit 31 (OWN) is reset in the TDES0. Specific frame
status information will be posted in the descriptor.
26.3.27 Ethernet DMA operation mode register (EMAC_DMAOPM)
The EMAC_DMAOPM register defines the receive and transmit operation modes and commands. This
register should be the last CSR to be written during DMA initialization. This register is also applicable
to GMAC-MTL configuration where the unused and reserved bits are 24, 13, 2 and 1. A delay value
greater than 4us is required between two consecutive write accesses to this register.