IXF1104
Refer to Figure 42 “MDC
5.5.5Management Frames
The Management Interface serializes the external register access information into the format specified by IEEE 802.3, Section 22.2.4.5 (see Figure 21).
Figure 21. Management Frame Structure
Preamble | Start | Op Code | PHY Addr | REG Addr Turnaround | Data | ||
2 Bits | 2 Bits | 5 Bits | 5 Bits | 2 Bits | 16 Bits | ||
32 Bits | |||||||
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First Bit Transmitted |
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| Last Bit Transmitted | ||||
5.5.6Single MDI Command Operation
The Management Data Interface is accessed through the “MDIO Single Command ($0x680)" and the “MDIO Single Read and Write Data ($0x681)". A single management frame is sent by setting Register 0, bit 20 to logic 1, and is automatically cleared when the frame is completed.
The Write data is first set up in Register 1, bits 15:0 for Write operation. Register 0 is initialized with the appropriate control information (start, op code, etc.) and Register 0, bit 20 is set to logic 1. Register 0, bit 20 is reset to logic 0 when the frame is complete.
The steps are identical for Read operation except that in Register 1, bits 15:0, the data is ignored. The data received from the MDIO is read by the CPU interface from Register 1, bits 31:16.
5.5.7MDI State Machine
The MDI State Machine sequences the information sent to it by the MDIO control registers and keeps track of the current sequence bit count, enabling or disabling the MDIO driver output (see Figure 22.
100 | Datasheet |
Document Number: 278757
Revision Number: 007
Revision Date: March 25, 2004
