82555 — Networking Silicon
Twisted Pair Ethernet (TPE) receiver is greater than 585 mV and less than 3.1 V. The TPE receive buffer distinguishes valid receive data, link test pulses, and the idle condition, according to the requirements of the
The following line activity is determined to be inactive and is rejected:
•Differential pulses of peak magnitude less than 300 mV.
•Continuous sinusoids with a differential amplitude less than 6.2 Vpp and frequency less than 2 MHz.
•Sine waves of a single cycle duration starting with 0° or 180° phase that have a differential
amplitude less than 6.2 Vpp and a frequency of at least 2 MHz and not more than 16 MHz. These
All other activity is determined to be either data, link test pulses,
5.3.310BASE-T Error Detection and Reporting
In 10 Mbps mode, the 82555 can detect errors in the receive data. The following condition is considered an error:
The receive pair’s voltage level drops to the idle state during reception before the
5.410BASE-T Collision Detection
Collision detection in 10 Mbps mode is indicated by simultaneous transmission and reception. If the 82555 detects this condition, it asserts a collision indication to the controller.
5.510BASE-T Link Integrity
The link integrity in 10 Mbps works with link pulses. The 82555 senses and differentiates those link pulses from fast link pulses and from
5.610BASE-T Jabber Control Function
The 82555 contains a jabber control function that inhibits transmission after a specified time window when enabled. In 10 Mbps mode, the jabber timer is set to a value between 26.2 ms and 39 ms. If the 82555 detects continuous transmission that is greater than this time period, it prevents further transmissions from onto the wire until it detects that the MAC transmit enable signal has been inactive for at least 314 ms.
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