Datasheet

ManualsBrandsMicrochip ManualsARM MicrocontrollersARM SAM Microcontroller 2MB LQFP

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1588 version 2 introduces transparent clocks of which there are two kinds, peer-to-peer (P2P) and end-to-end (E2E).

ransparent clocks measure the transit time of event messages through a bridge and amend a correction field within

the message to allow for the transit time. P2P transparent clocks additionally correct for the delay in the receive path

of the link using the information gathered from the peer delay frames. With P2P transparent clocks delay_req

messages are not used to measure link delay. This simplifies the protocol and makes larger systems more stable.

The GMAC recognizes four different encapsulations for PTP event messages:

1. 1588 version 1 (UDP/IPv4 multicast)

2. 1588 version 2 (UDP/IPv4 multicast)

3. 1588 version 2 (UDP/IPv6 multicast)

4. 1588 version 2 (Ethernet multicast)

Table 38-6. Example of Sync Frame in 1588 Version 1 Format

Frame Segment Value

Preamble/SFD 55555555555555D5

DA (Octets 0–5) —

SA (Octets 6–11) —

Type (Octets 12–13) 0800

IP stuff (Octets 14–22) —

UDP (Octet 23) 11

IP stuff (Octets 24–29) —

IP DA (Octets 30–32) E00001

IP DA (Octet 33) 81 or 82 or 83 or 84

Source IP port (Octets 34–35) —

Dest IP port (Octets 36–37) 013F

Other stuff (Octets 38–42) —

Version PTP (Octet 43) 01

Other stuff (Octets 44–73) —

Control (Octet 74) 00

Other stuff (Octets 75–168) —

Table 38-7. Example of Delay Request Frame in 1588 Version 1 Format