
EMAC Registers
1006
SLAU723A – October 2017 – Revised October 2018
Copyright © 2017–2018, Texas Instruments Incorporated
Ethernet Controller
15.6.48 EMACTARGNANO Register (Offset = 0x720) [reset = 0x0]
Ethernet MAC Target Time Nanoseconds (EMACTARGNANO)
The MAC Target Time Seconds (EMACTARGSEC) register, along with the MAC Target Time
Nanoseconds (EMACTARGNANO) register, is used to schedule an interrupt event.
EMACTARGNANO is shown in
and described in
Return to
Figure 15-63. EMACTARGNANO Register
31
30
29
28
27
26
25
24
TRGTBUSY
TTSLO
R/W-0x0
R/W-0x0
23
22
21
20
19
18
17
16
TTSLO
R/W-0x0
15
14
13
12
11
10
9
8
TTSLO
R/W-0x0
7
6
5
4
3
2
1
0
TTSLO
R/W-0x0
Table 15-72. EMACTARGNANO Register Field Descriptions
Bit
Field
Type
Reset
Description
31
TRGTBUSY
R/W
0x0
Target Time Register Busy. This bit is set and cleared by the MAC.
0x0 = The Ethernet MAC Target Time Seconds/Nanoseconds
(EMACTARGSEC/EMACTARGNANO) registers are not busy.
0x1 = The Ethernet MAC Target Time Seconds/Nanoseconds
(EMACTARGSEC/EMACTARGNANO) registers are busy. This bit is
set when the PPSCTRL field in the EMACPPSCTRL register is
programmed to 0x2 or 0x3 and the MAC is instructed to synchronize
the EMACTARGSEC/EMACTARGNANO registers to the PTP clock
domain. The EMACTARGSEC and EMACTARGNANO registers
must not be updated when this bit is read as 1.
30-0
TTSLO
R/W
0x0
Target Timestamp Low Register. This register stores the time in
(signed) nanoseconds. When the value of the timestamp matches
both EMACTARGx registers, the MAC starts or stops the PPS signal
output and generates an interrupt (if enabled) based on the
TRGMODS0 field in the MAC PPS Control (EMACPPSCTRL)
register. This value should not exceed 0x3B9A.C9FF when
DGTLBIN is set in the EMACTIMSTCTRL register. The actual start
or stop time of the PPS signal output may have an error margin up
to one unit of sub-second increment value.