
RM0008
Ethernet (ETH): media access control (MAC) with DMA controller
Doc ID 13902 Rev 12
1025/1096
Address offset: 0x0704
Reset value: 0x0000 0000
This register contains the 8-bit value by which the subsecond register is incremented. In
Coarse update mode (TSFCU bit in ETH_PTPTSCR), the value in this register is added to
the system time every clock cycle of HCLK. In Fine update mode, the value in this register is
added to the system time whenever the accumulator gets an overflow.
Ethernet PTP time stamp high register (ETH_PTPTSHR)
Address offset: 0x0708
Reset value: 0x0000 0000
This register contains the most significant (higher) 32 time bits. This read-only register
contains the seconds system time value. The Time stamp high register, along with Time
stamp low register, indicates the current value of the system time maintained by the MAC.
Though it is updated on a continuous basis.
Bit 1
TSFCU:
Time stamp fine or coarse update
When set, this bit indicates that the system time stamp is to be updated using the Fine Update
method. When cleared, it indicates the system time stamp is to be updated using the Coarse
method.
Bit 0
TSE:
Time stamp enable
When this bit is set, time stamping is enabled for transmit and receive frames. When this bit is
cleared, the time stamp function is suspended and time stamps are not added for transmit and
receive frames. Because the maintained system time is suspended, you must always initialize
the time stamp feature (system time) after setting this bit high.
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Reserved
STSSI
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Bits 31:8 Reserved
Bits 7:0
STSSI:
System time subsecond increment
The value programmed in this register is added to the contents of the subsecond value of the
system time in every update.
For example, to achieve 20 ns accuracy, the value is: 20 / 0.467 = ~ 43 (or 0x2A).
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STS
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Bits 31:0
STS:
System time second
The value in this field indicates the current value in seconds of the System Time maintained by
the core.