Texas Instruments TMS320C3x User Manual

Page 434

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DMA Controller

12-55

Peripherals

Table 12–6. DMA Global-Control Register Bits Summary (Continued)

Abbreviation

Reset

Value

Name

Description

INCSRC

0

DMA source address
increment mode

If INCSRC = 1, the source address is incremented after every
read.

DECSRC

0

DMA source address
decrement mode

If DECSRC = 1, the source address is decremented after
every read.

If INCSRC = DECSRC, the source address is not modified
after a read.

INCDST

0

DMA destination
address increment
mode

If INCDST = 1, the destination address is incremented after
every write.

DECDST

0

DMA destination
address decrement
mode

If DECDST = 1, the destination address is decremented after
every write.

If INCDST = DECDST, the destination address is not modified
after a write.

SYNC

0

DMA synchronization
mode

Determines the timing synchronization between the events
initiating the source and destination transfers.

The following table summarizes the SYNC bits and DMA
synchronization.

Bit 9

Bit 8

Function

0

0

No synchronization. Enabled interrupts
are ignored (reset value).

0

1

Source synchronization. A read is per-
formed when an enabled interrupt occurs.

1

0

Destination synchronization. A write is per-
formed when an enabled interrupt occurs.

1

1

Source and destination synchronization. A
read is performed when an enabled interrupt
occurs. A write is then performed when the
next

enabled interrupt occurs.

TC

0

DMA transfer mode

Affects the operation of the transfer counter.

If TC = 0, transfers are not terminated when the transfer
counter becomes 0.

If TC = 1, transfers are terminated when the transfer
counter becomes 0.

TCINT

0

DMA transfer counter
interrupt mode

If TCINT = 1, the DMA interrupt is set when the transfer
counter makes a transition to 0.

If TCINT = 0, the DMA interrupt is not set when the transfer
counter makes a transition to 0.

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