SH7619 Datasheet, PDF (686/836 Pages) Renesas Technology Corp – 32-Bit RISC Microcomputer SuperHTM RISC engine Family / SH7619 Series

Section 22 Ethernet Physical Layer Transceiver (PHY)
(2) Auto-negotiation
The purpose of the Auto-negotiation function is to automatically configure the PHY to the
optimum link parameters based on the capabilities of its link partner. Auto-negotiation is a
mechanism for exchanging configuration information between two link-partners and automatically
selecting the highest performance mode of operation supported by both sides. Auto-negotiation is
fully defined in clause 28 of the IEEE 802.3 specification.
Once auto-negotiation has completed, information about the resolved link can be passed back to
the controller (EtherC) via the Serial Management Interface (SMI). The results of the negotiation
process are reflected in the Link Partner Ability Register (Register 5).
The auto-negotiation protocol is a purely physical layer activity and proceeds independently of the
MAC controller (EtherC).
The advertised capabilities of the PHY are stored in register 4 of the SMI registers. The default
advertised by the core PHY is determined by user-defined on-chip signal options. (i.e. the
configuration of PHY-IF)
The following blocks are activated during an Auto-negotiation session:
• Auto-negotiation (digital)
• 100M ADC (analog)
• 100M PLL (analog)
• 100M equalizer/BLW/clock recovery (DSP)
• 10M SQUELCH (analog)
• 10M PLL (analog)
• 10M Transmitter (analog)
When enabled, auto-negotiation is started by the occurrence of one of the following events:
• Module reset (co_resetb of PHY-IF)
• PHY power on reset
• Software reset
• Power-down reset
• Link status down
• Setting register 0, bit 9 high (auto-negotiation restart)
Rev. 5.00 Mar. 15, 2007 Page 648 of 794
REJ09B0237-0500