Altera Cyclone V Device Handbook page 906

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2013.12.30
1. Program the start time for the next pulse in the Target Time registers (register 455 and 456). This time
should be more than the time at which the falling edge occurs for the previous pulse. †
2. Program the width of the next PPS signal output in Register 473 (PPS0 Width Register). †
3. Program Bits [3:0], PPSCMD, of Register 459 (PPS Control Register) to generate a single pulse after the
time at which the previous pulse is de-asserted. This instructs the MAC to generate single pulse on the
PPS signal output, at the time programmed in Target Time registers. If you give this command before
the previous pulse becomes low, then the new command overwrites the previous command and the
EMAC may generate only 1 extended pulse.
Generating a Pulse Train on PPS
To generate a pulse train on PPS:
1. Program 11 or 10 (for interrupt) in Bits [6:5], TRGTMODSEL, of Register 459 (PPS Control Register).
This instructs the MAC to use the Target Time registers (register 455 and 456) for start time of the PPS
signal output.
2. Program the start time value in the Target Time registers (register 455 and 456).
3. Program the interval value between the train of pulses on the PPS signal output in Register 473 (PPS0
Width Register).
4. Program the width of the PPS signal output in Register 473 (PPS0 Width Register).
5. Program Bits[3:0], PPSCMD, of Register 459 (PPS Control Register) to 0010. This instructs the MAC to
generate train of pulses on the PPS signal output with start time programmed in Target Time registers
(register 455 and 456). By default, the PPS pulse train is free-running unless stopped by 'STOP Pulse
train at time' or 'STOP Pulse Train immediately' commands.
6. Program the stop value in the Target Time registers (register 455 and 456). Ensure that Bit 31 (TSTRBUSY)
of Register 456 (Target Time Nanoseconds Register) is reset before programming the Target Time registers
(register 455 and 456) again.
7. Program the PPSCMD field (bit 3:0) of Register 459 (PPS Control Register) to 0100. This stops the train
of pulses on PPS signal output after the programmed stop time specified in
You can stop the pulse train at any time by programming 0101 in the PPSCMD field. Similarly, you can
cancel the Stop Pulse train command (given in
before the time (programmed in
programming 0011 in the PPSCMD field before the programmed start time (in
Generating an Interrupt without Affecting the PPS
The Bits [6:5], TRGTMODSEL, of the Register 459 (PPS Control Register) enable you to program the Target
Time registers (register 455 and 456) to do any one of the following: †
• Generate only interrupts. †
• Generate interrupts and the PPS start and stop time. †
• Generate only PPS start and stop time. †
To program the Target Time registers (register 455 and 456) to generate only interrupt event: †
1. Program 00 (for interrupt) in Bits [6:5], TRGTMODSEL, of Register 459 (PPS Control Register). This
instructs the MAC to use the Target Time registers (register 455 and 456) for target time interrupt. †
2. Program a target time value in the Target Time registers (register 455 and 456). This instructs the MAC
to generate an interrupt when the target time elapses. If Bits [6:5], TRGTMODSEL, are changed (for
Ethernet Media Access Controller
Send Feedback
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6 on page 1-57) elapses. You can cancel the pulse train generation by
Generating a Pulse Train on PPS
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7 on page 1-57) by programming 0110 in the PPSCMD field
17-57
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6 on page 1-57 elapses.
2 on page 1-57) elapses.
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