The Ethernet module provides the flexibility to program the start or stop time, width, and interval of the pulse generated on the ptp_pps_o output.
Note: By default, the module is in the “Fixed
Pulse-Per-Second Output” mode and indicated 1
second arrival. The frequency of the PPS output
can be changed by setting the PPSCTRL0 field in
the MAC_PPS_Control register.
The Ethernet module provides features such as programming the start or stop time, with the flexible PPS output option.
The Ethernet module supports the following features with the flexible PPS output option:
- Programming the start or stop time in terms of system time.
- Programming the start point of the single pulse and start and stop points of the pulse train in terms of 64-bit system time. The Target Time registers are used to program the start and stop time.
- Programming the stop time in advance, that is, you can program the stop time before the actual start time has elapsed.
- Programming the width between the rising edge and corresponding falling edge
of PPS signal output in terms of number of units
of sub-second increment value programmed in the
MAC_Sub_Second_Increment register. You can program
the width of pulse from 1 to 232-1 units of
sub-second increment value.
- Programming the interval, between the rising edges of PPS signal, in terms of number of units of sub-second increment value. You can program the interval between pulses from 1 to 232-1 units of sub-second increment value.
- Option to cancel the programmed PPS start or stop request.
- Error if the start or stop time being programmed has already elapsed.
Note: The PTP Reference clock mentioned in the
following sections is the clock at which the
system time gets updated. When the TSCFUPDT bit of
the MAC_Timestamp_Control register is set to 0,
this clock is similar to the clk_ptp_ref_i clock.
In the Fine Correction mode, this is the clock
tick at which the system time gets updated (using
incr_sub_sec_reg shown in
Figure 43-12).