
EMAC Registers
999
SLAU723A – October 2017 – Revised October 2018
Copyright © 2017–2018, Texas Instruments Incorporated
Ethernet Controller
15.6.41 EMACSUBSECINC Register (Offset = 0x704) [reset = 0x0]
Ethernet MAC Sub-Second Increment (EMACSUBSECINC)
In the Coarse Update mode (enabled by the TSCFUPDT bit in the MAC Timestamp Control
(EMACTIMSTCTRL) register), the value in the EMACSUBSECINC register is added to the system time
every clock cycle of slave clock reference, MOSC. In the Fine Update mode, the value in this register is
added to the system time whenever the Accumulator gets an overflow.
EMACSUBSECINC is shown in
and described in
Return to
Figure 15-56. EMACSUBSECINC Register
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
RESERVED
SSINC
R-0x0
R/W-0x0
Table 15-65. EMACSUBSECINC Register Field Descriptions
Bit
Field
Type
Reset
Description
31-8
RESERVED
R
0x0
7-0
SSINC
R/W
0x0
Sub-second Increment Value. The value programmed in this field is
accumulated every clock cycle (MOSC) with the contents of the sub-
second register. For example, when MOSC is 25 MHz (period is 40
ns), SSINC should be programmed with the value 40 (0x28) when
the Ethernet MAC System Time - Nanoseconds (EMACTIMNANO)
register has an accuracy of 1 ns (DGTLBIN bit is set in
EMACTIMSTCTRL). When DGTLBIN bit is clear, the
EMACTIMNANO register has a resolution of ~0.465ns. In this case,
a value of 86 (0x56), that is derived by 40ns/0.465, should be
programmed in the SSINC field.