HS_Media independent interface (MII)
RM0082
512/844
Doc ID 018672 Rev 1
[02]
ED
Excessive Deferral. If set, it indicates that the transmission has ended
because of excessive deferral of over 24288 bit times (155680 bit times in
Jumbo Frame Enabled Mode), if the DC (Deferral Check) bit in the MAC
Configuration register (Register 0) is set.
[01]
UF
Underflow Error. If set, it indicates that the transmission has ended because
data arrived late from the host memory. This means that DMA encountered
an empty Transmit Buffer while transmitting the frame.
[00]
DB
Deferred Bit. If set, it indicates that the MAC defers before transmission
because of the presence of carrier. Valid in half-duplex mode only.
Table 415.
Transmit descriptor 1 (TEDS1)
Bit
Name
Description
[31:29]
Reserved
-
[28:16]
TBS2
Transmit Buffer 2 Size. These 13 bit field reports the size (in bytes) of the
second data buffer.
Note: This field is not valid if TDES0[20] is set.
[15:13]
Reserved
-
[12:00]
TBS1
Transmit Buffer 1 Size. These 13 bit field reports the size (in bytes) of the first
data buffer.
Note: If TBS1 value is 13h’0, then the DMA ignores this buffer and uses the
2nd buffer or next descriptor (depending on TCH bit value).
Table 416.
Transmit descriptor 2 (TDES2)
Bit
Name
Description
[31:00]
Buffer 1
Address
Pointer
This field indicates the physical address of the 1st data buffer
pointed to by this descriptor.
Table 417.
Transmit descriptor 3 (TDES3)
Bit
Name
Description
[31:00]
Buffer 2
Address
Pointer
This field indicates the physical address of the 2nd data buffer pointed to
by this descriptor, if descriptor chaining is used.
If TDES1[24] bit is set, then this field contains the pointer to the physical
memory when the next descriptor is present.
Table 414.
Transmit descriptor 0 (TDES0) (continued)
Bit
Name
Description