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Architecture

2.6.3Interrupt Control

The EMAC control module combines multiple interrupt conditions generated by the EMAC and MDIO modules into four separate interrupt signals (Table 5) that are mapped to a CPU interrupt via the CPU interrupt controller. The four separate sources of interrupt can be individually enabled for each channel by the CMRXTHRESHINTEN, CMRXINTEN, CMTXINTEN, and CMMISCINTEN registers.

Table 5. EMAC Control Module Interrupts

ARM Event

Acronym

Source

24

MAC_RXTH

EMAC receive threshold

25

MAC_RX

EMAC receive

26

MAC_TX

EMAC transmit

27

MAC_MISC

EMAC miscellaneous

2.6.3.1Transmit Pulse Interrupt

The EMAC control module receives the eight individual transmit interrupts originating from the EMAC module, one for each of the eight channels, and combines them into a single transmit pulse interrupt to the CPU. This transmit pulse interrupt is paced, as described in Section 2.6.4. The eight individual transmit pending interrupt(s) are selected at the EMAC control module level, by setting one or more bits in the EMAC control module transmit interrupt enable register (CMTXINTEN). The masked interrupt status can be read in the EMAC control module transmit interrupt status register (CMTXINTSTAT).

Upon reception of a transmit pulse interrupt, the ISR performs the following:

1.Read CMTXINTSTAT to determine which channel(s) caused the interrupt.

2.Process received packets for the interrupting channel(s).

3.Write the appropriate CPGMAC transmit channel n completion pointer register(s) (TXnCP) with the address of the last buffer descriptor of the last packet processed by the application software.

4.Write the MAC end of interrupt vector register (MACEOIVECTOR) in the EMAC module with a value of 2h to signal the end of the transmit interrupt processing.

2.6.3.2Receive Pulse Interrupt

The EMAC control module receives the eight individual receive interrupts originating from the EMAC module, one for each of the eight channels, and combines them into a single receive pulse interrupt to the CPU. This receive pulse interrupt is paced, as described in Section 2.6.4. The eight individual receive pending interrupt(s) are selected at the EMAC control module level, by setting one or more bits in the EMAC control module receive interrupt enable register (CMRXINTEN). The masked interrupt status can be read in the EMAC control module receive interrupt status register (CMRXINTSTAT).

Upon reception of a receive pulse interrupt, the ISR performs the following:

1.Read CMRXINTSTAT to determine which channel(s) caused the interrupt.

2.Process received packets for the interrupting channel(s).

3.Write the appropriate CPGMAC receive channel n completion pointer register(s) (RXnCP) with the address of the last buffer descriptor of the last packet processed by the application software.

4.Write the MAC end of interrupt vector register (MACEOIVECTOR) in the EMAC module with a value of 1h to signal the end of the receive interrupt processing.

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Ethernet Media Access Controller (EMAC)/Management Data Input/Output (MDIO)

SPRUEQ6–December 2007

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Texas Instruments TMS320DM646x manual Interrupt Control, Emac Control Module Interrupts, Transmit Pulse Interrupt
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TMS320DM646x specifications

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