Texas Instruments TMS320DM646x manual Interrupt Support, EMAC Module Interrupt Events and Requests

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Architecture

2.16 Interrupt Support

2.16.1EMAC Module Interrupt Events and Requests

The EMAC module generates the following interrupt events:

∙RXTHRESHOLDPENDn: Receive threshold interrupt for receive channels 0 through 7

∙RXPENDn: Receive packet completion interrupt for receive channels 0 through 7

∙TXPENDn: Transmit packet completion interrupt for transmit channels 0 through 7

∙STATPEND: Statistics interrupt

∙HOSTPEND: Host error interrupt

∙USERINT: MDIO user Interrupt

∙LINKINT: MDIO link Interrupt

As shown in Figure 12, the EMAC and MDIO interrupts are multiplexed on four interrupts lines going to the CPU.

Figure 12. EMAC Control Module Interrupt Logic Diagram

EMAC￿core

MDIO￿core

Interrupt￿control￿and￿pacing￿logic

RXTHRESHOLDPEND(0..7) Receive￿threshold￿interrupt

RXPEND(0..7)

Receive￿interrupt TXPEND(0..7)

Transmit￿interrupt

STATPEND

HOSTPEND

Miscellaneous￿interrupt

MDIO_USER

MDIO_LINKINT

2.16.1.1Receive Threshold Interrupts

Each of the eight receive channels have a corresponding receive threshold interrupt

(RX_THRESH_PEND[0:7]). The receive threshold interrupts are level interrupts that remain asserted until the triggering condition is cleared by the host. Each of the eight threshold interrupts may be individually enabled by setting the corresponding bit in the receive interrupt mask set register (RXINTMASKSET) to 1. Each of the eight channel interrupts may be individually disabled by clearing the corresponding bit in the receive interrupt mask clear register (RXINTMASKCLEAR) to 0. The raw and masked receive interrupt status may be read from the receive interrupt status (unmasked) register (RXINTSTATRAW) and the receive interrupt status (masked) register (RXINTSTATMASKED), respectively. An RX_THRES_PEND[7:0] interrupt bit is asserted when enabled and when the channel’s associated receive channel n free buffer count register (RXnFREEBUFFER) is less than or equal to the channel’s associated receive channel n flow control threshold register (RXnFLOWTHRESH). The receive threshold interrupts use the same free buffer count and threshold logic as does flow control, but the interrupts are independently enabled from flow control. The threshold interrupts are intended to give the host an indication that resources are running low for a particular channel(s).

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

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