...
P1_TS_RX_DEC
P1_TS_RX_MII
GMII_TX_0
P1_TS_TX_DEC
P1_TS_TX_MII
GMII_RX_n
Pn_TS_RX_DEC
Pn_TS_RX_MII
GMII_TX_n
Pn_TS_TX_DEC
Pn_TS_TX_MII
SCR
TSPUSH
EVENT_FIFO
REGS
EVNT_PEND
GMII_RX_0
RCLK
CPTS_RFT_CLK
TSCNTROLL
HW1_TS_PUSH
HW2_TS_PUSH
HW4_TS_PUSH
HW3_TS_PUSH
HW1_TS_PUSH
HW2_TS_PUSH
HW3_TS_PUSH
HW4_TS_PUSH
Functional Description
14.3.7 Common Platform Time Sync (CPTS)
The CPTS module is used to facilitate host control of time sync operations. It enables compliance with the
IEEE 1588-2008(v2) standard for a precision clock synchronization protocol.
14.3.7.1 Architecture
Figure 14-10. CPTS Block Diagram
shows the architecture of the CPTS module inside the 3PSW Ethernet Subsystem. Time
stamp values for every packet transmitted or received on either port of the 3PSW are recorded. At the
same time, each packet is decoded to determine if it is a valid time sync event. If so, an event is loaded
into the Event FIFO for processing containing the recorded time stamp value when the packet was
transmitted or received.
In addition, both hardware (HWx_TS_PUSH) and software (TS_PUSH) can be used to read the current
time stamp value though the Event FIFO
The reference clock used for the time stamp (RCLK) is sourced from one of the two sources, as shown in
. The source can be selected by configuring the CM_CPTS_RFT_CLKSEL register in the
Control Module. For more details, see
, Control Module.
14.3.7.2 Time Sync Overview
The CPTS module is used to facilitate host control of time sync operations. The CPTS collects time sync
events and then presents them to the host for processing. There are five types of time sync events
(ethernet receive event, ethernet transmit event, time stamp push event, time stamp rollover event, and
time stamp half-rollover event). Each ethernet port can cause transmit and receive events. The time stamp
push is initiated by software.
14.3.7.2.1 Time Sync Initialization
The CPTS module should be configured as shown:
•
Complete the reset sequence (VBUSP_RST_N) to reset the module.
1228
Ethernet Subsystem
SPRUH73H – October 2011 – Revised April 2013
Copyright © 2011–2013, Texas Instruments Incorporated