GMII Reception - 2.7 English

1G/10G/25G Switching Ethernet Subsystem Product Guide (PG292)

Document ID
PG292
Release Date
2022-05-11
Version
2.7 English

1/2.5 Gb/s Frame Reception

The timing of a normal inbound frame transfer is shown in the following figure.

Figure 1. GMII Frame Reception at 1 Gb/s

100 Mb/s Frame Reception

At 100 Mb/s the operation of the core is unchanged. When operating at a speed of 100 Mb/s, every byte of the MAC frame (from preamble to the frame check sequence field, inclusive) is repeated for 10 clock periods to achieve the desired bit rate. See the following figure.

Figure 2. GMII Data Reception at 100 Mb/s

10 Mb/s Frame Reception

The operation of the core remains unchanged. When operating at a speed of 10 Mb/s, every byte of the MAC frame (from preamble to the frame check sequence field, inclusive) is repeated for 100 clock periods to achieve the desired bit rate.