Texas Instruments TMS320DM646x manual Functional Block Diagram, Emac and Mdio Block Diagram

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Introduction

∙No-chain mode truncates frame to first buffer for network analysis applications.

∙Emulation support.

∙Loopback mode.

1.3Functional 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 and the EMAC module and MDIO module. The EMAC control module contains the necessary components to allow the EMAC to make efficient use of device memory, plus it controls device interrupts. The EMAC control module incorporates 8K-byte internal RAM to hold EMAC buffer descriptors.

The MDIO module implements the 802.3 serial management interface to interrogate and control up to 32 Ethernet PHYs connected to the device, 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 networked community. The EMAC on this device supports 10Base-T (10 Mbits/second) and 100BaseTX (100 Mbits/second) in either half-duplex or full-duplex mode and 1000BaseT(1000 Mbits/second) in full-duplex mode, with hardware flow control and quality-of-service (QOS) support.

Figure 1. EMAC and MDIO Block Diagram

ARM interrupt	Configuration bus
controller		DMA memory
		transfer controller
4
		Peripheral bus
EMAC/MDIO	EMAC control module
interrupts	EMAC module	MDIO module
	G/MII bus	MDIO bus

Figure 1 also shows the main interface between the EMAC control module and the CPU. The following connections are made to the device core:

∙The peripheral 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 module, EMAC, and MDIO 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 RAM is mapped into this same range.

∙The EMAC and MDIO interrupts are combined into a single interrupt within the control module. The interrupt from the control module then goes to the ARM interrupt controller.

SPRUEQ6–December 2007 Ethernet Media Access Controller (EMAC)/Management Data Input/Output (MDIO) 13

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