SMSC LAN9311i - Manual (Page 211)

Two Port 10/100 Managed Ethernet Switch with 16-Bit Non-PCI CPU Interface
Datasheet
SMSC LAN9311/LAN9311i 211 Revision 1.4 (08-19-08)
DATASHEET
14.2.5.10 GPIO 8 1588 Clock Low-DWORD Capture Register (1588_CLOCK_LO_CAPTURE_GPIO_8)
This read only register combined with the GPIO 8 1588 Clock High-DWORD Capture Register
(1588_CLOCK_HI_CAPTURE_GPIO_8) form the 64-bit GPIO 8 timestamp capture.
Offset: 164h Size: 32 bits
BITS DESCRIPTION TYPE DEFAULT
31:0 Timestamp Low (TS_LO)
This field contains the low 32-bits of the timestamp upon activation of GPIO
8. RO 00000000h