SAM7X128_14 Datasheet, PDF (554/662 Pages) ATMEL Corporation – ARM-based Flash MCU

37.5.4 Transmit Status Register
Register Name:
EMAC_TSR
Access Type:
Read-write
31
30
29
28
27
26
25
24
–
–
–
–
–
–
–
–
23
22
21
20
19
18
17
16
–
–
–
–
–
–
–
–
15
14
13
12
11
10
9
8
–
–
–
–
–
–
–
–
7
6
5
4
3
2
1
0
–
UND
COMP
BEX
TGO
RLE
COL
UBR
This register, when read, provides details of the status of a transmit. Once read, individual bits may be cleared by writing 1 to
them. It is not possible to set a bit to 1 by writing to the register.
• UBR: Used Bit Read
Set when a transmit buffer descriptor is read with its used bit set. Cleared by writing a one to this bit.
• COL: Collision Occurred
Set by the assertion of collision. Cleared by writing a one to this bit.
• RLE: Retry Limit exceeded
Cleared by writing a one to this bit.
• TGO: Transmit Go
If high transmit is active.
• BEX: Buffers exhausted mid frame
If the buffers run out during transmission of a frame, then transmission stops, FCS shall be bad and tx_er asserted. Cleared by
writing a one to this bit.
• COMP: Transmit Complete
Set when a frame has been transmitted. Cleared by writing a one to this bit.
• UND: Transmit Underrun
Set when transmit DMA was not able to read data from memory, either because the bus was not granted in time, because a not
OK hresp(bus error) was returned or because a used bit was read midway through frame transmission. If this occurs, the
transmitter forces bad CRC. Cleared by writing a one to this bit.
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
554