TM4C129ENCZAD Datasheet, PDF (1671/2037 Pages) Texas Instruments – Tiva Microcontroller

Tiva^™ TM4C129ENCZAD Microcontroller
Register 39: Ethernet MAC Sub-Second Increment (EMACSUBSECINC), offset
0x704
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.
Ethernet MAC Sub-Second Increment (EMACSUBSECINC)
Base 0x400E.C000
Offset 0x704
Type RW, reset 0x0000.0000
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
reserved
Type RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
Reset
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
reserved
SSINC
Type RO
RO
RO
RO
RO
RO
RO
RO
RW
RW
RW
RW
RW
RW
RW
RW
Reset
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Bit/Field
31:8
7:0
Name
reserved
SSINC
Type
RO
RW
Reset
0x0
0x0
Description
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
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.
June 18, 2014
Texas Instruments-Production Data
1671