11.3.2 Peripheral Interrupt Event Trigger Sources
The peripheral interrupt event trigger can be independently configured as one twenty-nine different sources for
each of the six DMA channels. Included in these sources are three external interrupt signals which can be
connected to most of the general-purpose input/output (GPIO) pins on the device. This adds significant flexibility
to the event trigger capabilities. A bit field called PERINTSEL in the MODE register of each channel is used
to select that channels interrupt trigger source. An active peripheral interrupt trigger will be latched into the
PERINTFLG bit of the CONTROL register, and if the respective interrupt and DMA channel is enabled (see
the MODE.CHx[PERINTE] and CONTROL.CHx[RUNSTS] bits), it will be serviced by the DMA channel. Upon
receipt of a peripheral interrupt event signal, the DMA will automatically send a clear signal to the interrupt
source so that subsequent interrupt events will occur.
Regardless of the value of the MODE.CHx[PERINTSEL] bit field, software can always force a trigger by using
the CONTROL.CHx[PERINTFRC] bit. Likewise, software can always clear a pending DMA trigger using the
CONTROL.CHx[PERINTCLR] bit.
Once a particular interrupt trigger sets a channel’s PERINTFLG bit, the bit stays pending until the priority logic
of the state machine starts the burst transfer for that channel. Once the burst transfer starts, the flag is cleared.
If a new interrupt trigger is generated while a burst is in progress, the burst will complete before responding to
the new interrupt trigger (after proper prioritization). If a third interrupt trigger occurs before the pending interrupt
is serviced, an error flag is set in the CONTROL.CHx[OVRFLG] bit. If a peripheral interrupt trigger occurs at the
same time as the latched flag is being cleared, the peripheral interrupt trigger has priority and the PERINTFLG
will remain set.
shows a diagram of the trigger select circuit. See the MODE.CHx[PERINTSEL] bit field description
for the complete list of peripheral interrupt trigger sources.
None
ADCINT1
ADCINT2
EPWM7SOCB
USB0EP3RX
USB0EP3TX
.
.
.
MODE.CHx
[PERINTSEL]
CONTROL.CHx
[PERINTFRC]
CONTROL.CHx
[PERINTCLR]
Clear
Set
Latch
Clear peripheral interrupt
trigger flag if appropriate
CONTROL.CHx[PERINTFLG]
Peripheral
Int
MODE.CHx
[PERINTE]
Clear interrupt
DMA
channel x
processing
logic
Figure 11-2. Peripheral Interrupt Trigger Input Diagram
shows the interrupt trigger source options that are available for each channel.
Direct Memory Access (DMA) Module
730
TMS320x2806x Microcontrollers
SPRUH18I – JANUARY 2011 – REVISED JUNE 2022
Copyright © 2022 Texas Instruments Incorporated
Содержание TMS320 2806 Series
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