Texas Instruments TMS320C645x DSP - Manual (Page 12)

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1.3 Functional Block Diagram
Configuration bus
DMA memory
transfer controller
Peripheral bus
EMAC control module
EMAC module MDIO module
MII MDIO bus
EMAC/MDIO
interrupt
Interrupt
controller
RMII GMII RGMII
Introduction
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 management data input / output (MDIO) module implements the 802.3 serial management interface to
interrogate and control up to 32 ethernet PHY(s) connected to the device, using a shared two–wire bus.
Application software uses the MDIO module to configure the auto-negotiation 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 ethernet media access controller (EMAC) module provides an efficient interface between the C645x
core processor and the networked community. The EMAC supports 10Base-T (10 Mbits / sec), and
100BaseTX (100 Mbits / sec), in either half or full duplex mode, and 1000BaseT (1000 Mbits / sec) in full
duplex mode, with hardware flow control and quality-of-service (QOS) support.
Figure 1. EMAC and MDIO Block Diagram
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 switch fabric interface.
•
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. The control module’s
internal RAM maps to this same range along with these registers.
•
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 device’s interrupt controller.
The EMAC and MDIO interrupts are combined within the control module, so only the control module
interrupt needs to be monitored by the application software or device driver. The interrupt is mapped to a
specific CPU interrupt via the enhanced interrupt selector within the C64x+ core. The combined EMAC /
MDIO interrupt maps to the interrupt controller input as system event 17.
Ethernet Media Access Controller (EMAC)/Management Data Input/Output (MDIO) 12 SPRU975B – August 2006
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