Functional Overview
3.12.10 DMA Interrupts
The ability of the DMA to interrupt the CPU based on the status of the data transfer is configurable and is
determined by the IMOD and DINM bits in the DMA transfer mode control register (DMMCRn). The available
modes are shown in Table 3−11.
Table 3−11. DMA Interrupts
MODE
ABU (non-decrement)
ABU (non-decrement)
Multi frame
DINM
IMOD
INTERRUPT
1
1
1
1
0
0
0
1
0
1
X
X
At full buffer only
At half buffer and full buffer
At block transfer complete (DMCTRn = DMSEFCn[7:0] = 0)
At end of frame and end of block (DMCTRn = 0)
No interrupt generated
Multi frame
Either
Either
No interrupt generated
3.12.11 DMA Controller Synchronization Events
The transfers associated with each DMA channel can be synchronized to one of several events. The DSYN
bit field of the DMSEFCn register selects the synchronization event for a channel. The list of possible events
and the DSYN values are shown in Table 3−12.
Table 3−12. DMA Synchronization Events
DSYN VALUE
0000b
0001b
0010b
0011b
0100b
0101b
0110b
0111b
DMA SYNCHRONIZATION EVENT
No synchronization used
McBSP0 receive event
McBSP0 transmit event
McBSP2 receive event
McBSP2 transmit event
McBSP1 receive event
McBSP1 transmit event
†
UART
1000b
1001b
1010b
1011b
1100b
1101b
1110b
Reserved
Reserved
Reserved
Reserved
Reserved
Timer 0 interrupt event
External interrupt 3
Timer 1 interrupt event
1111b
†
Note that the UART DMA synchronization event is usable as a synchronization event only, and is not usable
for transferring data to or from the UART. The DMA cannot be used to transfer data to or from the UART.
The DMA controller can generate a CPU interrupt for each of the six channels. However, due to a limit on the
number of internal CPU interrupt inputs, channels 0, 1, 2, and 3 are multiplexed with other interrupt sources.
DMA channels 0, 1, 2, and 3 share an interrupt line with the receive and transmit portions of the McBSP. When
the 5407/5404 is reset, the interrupts from these three DMA channels are deselected. The INT0SEL bit field
in the DMPREC register can be used to select these interrupts, as shown in Table 3−13.
48
SPRS007D
November 2001 − Revised April 2004
TI [ TEXAS INSTRUMENTS ]
