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Introduction
1.3 Functional Block Diagram
Figure 1 shows the three main functional modules of the EMAC/MDIO peripheral:
• EMAC control module
• EMAC module
• MDIO module
The EMAC control module is the main interface between the device core processor to the EMAC and
MDIO modules. The EMAC control module controls device interrupts and incorporates an 8k-byte internal
RAM to hold EMAC buffer descriptors (also known as CPPI RAM).
The MDIO module implements the 802.3 serial management interface to interrogate and control up to 32
Ethernet PHYs connected to the device by using a shared two-wire bus. Host software uses the MDIO
module to configure the autonegotiation parameters of each PHY attached to the EMAC, retrieve the
negotiation results, and configure required parameters in the EMAC module for correct operation. The
module is designed to allow almost transparent operation of the MDIO interface, with very little
maintenance from the core processor.
The EMAC module provides an efficient interface between the processor and the network. The EMAC on
this device supports 10Base-T (10 Mbits/sec) and 100BaseTX (100 Mbits/sec), half-duplex and full-duplex
mode, and hardware flow control and quality-of-service (QOS) support.
Figure 1 shows the main interface between the EMAC control module and the CPU. The following
connections are made to the device core:
• The DMA bus connection from the EMAC control module allows the EMAC module to read and write
both internal and external memory through the DMA memory transfer controller.
• The EMAC control, EMAC, and MDIO modules all have control registers. These registers are
memory-mapped into device memory space via the device configuration bus. Along with these
registers, the control module’s internal CPPI RAM is mapped into this same range.
• The EMAC and MDIO interrupts are combined into four interrupt signals within the control module.
Three configurable interrupt cores within the control module receive all four interrupt signals from the
combiner and submit interrupt requests to the CPU.
Figure 1. EMAC and MDIO Block Diagram
13
SPRUFL5B–April 2011 EMAC/MDIO Module
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