
DMA Registers
11-10
TCC
Transfer counter interrupt control. If TCC = 1 a DMA channel interrupt pulse
is sent to the CPU after the transfer counter makes a transition to zero and
the write of the last transfer is complete.
If enabled, the corresponding DMA interrupt (DMA INT0–INT5) occurs at the
vector shown in Figure 7–2. If TCC = 0 a DMA channel interrupt pulse is not
sent to the CPU when the transfer counter transitions to zero. This bit affects
unified mode and the primary channel in split mode.
AUX TCC
Auxiliary transfer counter interrupt control.
If bit = 1 a DMA channel interrupt
pulse is sent to the CPU after the auxiliary transfer counter makes a transi-
tion to zero and the write of the last transfer is complete. If enabled, the corre-
sponding DMA interrupt (DMA INT0–INT5) occurs as shown in Figure 7–2.
If bit = 0 a DMA channel interrupt pulse is not sent to the CPU when the auxil-
iary transfer counter transitions to zero. This bit affects the auxiliary channel
in split mode only.
TCINT FLAG
Transfer counter interrupt flag. This flag is set to 1 whenever the transfer
counter makes a transition to zero and the write of the last transfer is com-
pleted. Whenever the DMA channel control register is read, this flag is
cleared, unlessthe flag is being set by the DMA in the same cycle as the
read. The TCINT FLAG is affected by the unified mode and the primary chan-
nel in split mode.
AUX
TCINT FLAG
Auxiliary transfer counter interrupt flag. This flag is set to 1 whenever the
auxiliary transfer counter makes a transition to zero and the write of the last
transfer is completed. Whenever the DMA control register is read, this flag
is cleared, unlessthe flag is being set by the DMA coprocessor in the same
cycle as the read. The AUX TCINT FLAG is affected by the auxiliary channel
in split mode. Since only one interrupt is available for a DMA channel, you
can determine what event had set the interrupt by examining the TCINT
FLAG and the AUX TCINT FLAG.
START
Starts and stops the DMA channel in several different ways (as are listed in
Table 11–5). START affects the unified mode and the primary channel in split
mode. If they is used to hold a channel in the middle of an autoinit sequence,
the START and AUX START bits will hold the autoinit sequence. If the
START or AUX START bits are being modified by the DMA channel (for ex-
ample, to force a halt code of 10
2
on a transfer-counter terminated block
transfer) and a write is being performed by an external source to the DMA
channel control register, internal modification of the START or AUX START
bits by the DMA channel has priority. See TRANSFER MODE bits value of
01
2
in Table 11–2 for more information.
AUX START
Starts and stops the DMA channel in several different ways (as are listed in
Table 11–5). AUX START affects the auxiliary channel in split mode only.