AT32F435/437
Series Reference Manual
2022.11.11
Page 636
Rev 2.03
This bit must be read as 0 before being updated. This bit
is cleared after the initialization. Time stamp high word
register (if enabled) is not updated.
Bit 1
TFCU
0x0
rw
Timestamp Fine or Coarse Update
When this bit is set, it indicates that the system time is
updated using a fine update method. When this bit is
cleared, it indicates that the system time is updated using
a coarse update method.
Bit 0
TE
0x0
rw
Timestamp Enable
When this bit is set, time stamp function is enabled for
transmit and receive frames. Once disabled, the time
stamp function is not added for transmit and receive
frames, and the time stamp generator is suspended as
well. Once enabled, the time stamp (system time) should
be initialized. On the receive side, the MAC processes
1588 frames only when this bit is set.
Correlation between time stamp snapshot and register bits
SPPFTS
Bit 17: 16
ESFMRTM
Bit 15
ETSFEM
Bit 14
PTP message
00 or 01
X
0
SYNC, Follow_Up, Delay_Req, Delay_Resp
00 or 01
1
1
Delay_Req
00 or 01
0
1
SYNC
10
N/A
0
SYNC, Follow_Up, Delay_Req, Delay_Resp
10
N/A
1
SYNC, Follow_Up
11
N/A
0
SYNC, Follow_Up, Delay_Req, Delay_Resp, Pdelay_Req,
Pdelay_Resp
11
N/A
1
SYNC, Pdelay_Req, Pdelay_Resp
1 : N/A= Not applicable
2 : X=Irrelevant
26.3.46 Ethernet PTP subsecond increment register
(EMAC_PTPSSINC)
This register is present only when the IEEE1588 time stamp function is selected without an external
time stamp input. In Coarse Update mode (TSCFUPDT bit), the value in this register is added to the
system time every clk_ptp_ref_i clock cycle. In Fine Update mode, the value in this register is added to
the system time whenever the accumulator has an overflow.
Bit
Register
Reset value
Type
Description
Bit 31: 8
Reserved
0x000000
resd
Kept at its default value.
Bit 7: 0
SSIV
0x00
rw
Sub-Second Increment Value
The value programmed in this field is incremented with the
value of the subsecond register at every clock cycle (of
clk_ptp_i). For example, if the PTP clock is 50 MHz (20
ns), when the system time nanosecond register is 1 ns
accuracy (by setting the bit 9 in the EMAC_PTPTSCTRL
register), the value of these bits should be configured to
20 (0x14). When the TSCTRLSSR is cleared, nanosecond
register resolution is ~0.465ns accuracy. In this case, the
value of these bits should be configured to 43 (0x2B), that
is, 20ns/0.465.
26.3.47 Ethernet PTP time stamp high register (EMAC_PTPTSH)
System time second register and system time nanosecond register indicate the current value of the
system time maintained by the MAC. This value is updated on a continuous basis.
Bit
Register
Reset value
Type
Description
Bit 31: 0
TS
0x0000 0000 ro
Timestamp Second
This field indicates the second value of the current system
time maintained by the MAC.