VSC7440 datasheet(346/444 Pages) MICROSEMI

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VCore-III System and CPU Interfaces

VMDS-10492 VSC7440 Datasheet Revision 4.2

329

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The FRM (frame) counter is incremented by one each time the FDMA store status word for DCB that

has EOF set. It is a wrapping counter that can be used for software driver debug and development.

This counter does not count aborted frames.

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The DCB counter is incremented by one every time the FDMA loads a DCB from memory. It is a

wrapping counter that can be used for software driver debug and development.

It is possible to enable channel interrupt whenever the SIG counter is incremented; this makes it possible

for software to receive interrupt when the FDMA reaches certain points in a DCB chain.

4.7.4

FDMA Events and Interrupts

Each FDMA channel can generate four events: LLP-event, FRM-event, SIG-event, and ERR-event.

These events cause a bit to be set in FDMA_INTR_LLP.INTR_LLP[ch],

FDMA_INTR_FRM.INTR_FRM[ch], FDMA_INTR_SIG.INTR_SIG[ch], and

FDMA_EVT_ERR.EVT_ERR[ch], respectively.

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LLP-event occurs when an extraction channel loads a DCB that has LLP = NULL or when an

injection channel writes status for a DCB that has LLP=NULL. LLP-events are also emitted from

channels that have FDMA_CH_CFG[ch].DONEEOF_STOP_ENA or

FDMA_CH_CFG[ch].DONE_STOP_ENA set. For more information, see Enabling and Disabling

FDMA Channels.

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FRM-event is indicated when an active channel loads a new DCB and the previous DCB had EOF.

The FRM-event is also indicated for channels that are disabled after writing DCB status with EOF.

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SIG-event is indicated whenever the FDMA_CH_CNT[ch].CH_CNT_SIG counter is incremented.

The SIG (signal) counter is incremented when loading a DCB that has the DATAL.SIG bit set.

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ERR-event is an error indication that is set for a channel if it encounters an unexpected problem

during normal operation. This indication is implemented to ease software driver debugging and

development. A channel that encounters an error will be disabled, depending on the type of error the

channel state may be too corrupt for it to be restarted without system reset. When an ERR-event

occurs, the FDMA_EVT_ERR_CODE.EVT_ERR_CODE shows the exact reason for an ERR-event.

For more information about the errors that are detected, see

FDMA_EVT_ERR_CODE.EVT_ERR_CODE.

Each of the events (LLP, FRM, SIG) can be enabled for channel interrupt through

FDMA_INTR_LLP_ENA.INTR_LLP_ENA[ch], FDMA_INTR_FRM_ENA.INTR_FRM_ENA[ch], and

FDMA_INTR_SIG.INTR_SIG[ch] respectively. The ERR event is always enabled for channel interrupt.

The highest numbered extraction channel supports two additional non-sticky events related to manual

extraction: XTR_SOF_RDY-event and XTR_ANY_RDY-event. An active event causes the following fields

to be set: MANUAL_INTR.INTR_XTR_SOF_RDY and MANUAL_INTR.INTR_XTR_ANY_RDY

respectively. For more information, see Manual Extraction.

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XTR_SOF_RDY-event is active when the next word to be manually extracted contains an SOF

indication. This event is enabled in MANUAL_INTR_ENA.INTR_XTR_SOF_RDY_ENA.

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XTR_ANY_RDY-event is active when any word is available for manually extraction. This event is

enabled in MANUAL_INTR_ENA.INTR_XTR_ANY_RDY_ENA respectively.

The highest numbered injection channel supports one additional non-sticky event related to manual

injection: INJ_RDY-event. This event is active when the injection logic has room for (at least) sixteen 32-

bit words of injection frame data. When this event is active, MANUAL_INTR.INTR_INJ_RDY is set. The

INJ_RDY-event can be enabled for channel interrupt by setting

MANUAL_INTR_ENA.INTR_INJ_RDY_ENA. For more information, see Manual Injection.

The FDMA_INTR_ENA.INTR_ENA[ch] field enables interrupt from individual channels,

FDMA_INTR_IDENT.INTR_IDENT[ch] field shows which channels that are currently interrupting. While

INTR_IDENT is non-zero, the FDMA is indicating interrupting towards to the VCore-III interrupt controller.

The following illustration shows the FDMA channel interrupt hierarchy.

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