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The transfer count is specified as a 16-bit value in ETCR. The ETCR value is decremented by 1 at
each transfer. When the ETCR value reaches H'0000, the DTE bit is cleared, the transfer ends, and
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a CPU interrupt is requested. The maximum transfer count is 65,536, obtained by setting ETCR to
H'0000.
Transfers can be requested (activated) by compare match/input capture A interrupts from ITU
channels 0 to 3, transmit-data-empty and receive-data-full interrupts from SCI channel 0, and
external request signals.
For the detailed settings see section 8.2.4, Data Transfer Control Registers (DTCR).
Figure 8-5 shows a sample setup procedure for idle mode.
Idle mode setup
Set source and
destination addresses
Set transfer count
Read DTCR
Set DTCR
Idle mode
1.
Set the source and destination addresses
in MAR and IOAR. The transfer direction is deter-
mined automatically from the activation source.
2.
Set the transfer count in ETCR.
1
3.
Read DTCR while the DTE bit is cleared to 0.
4.
Set the DTCR bits as follows.
•
Select the DMAC activation source with bits
DTS2 to DTS0.
•
Set the DTIE and RPE bits to 1 to select idle mode.
2
•
Select byte size or word size with the DTSZ bit.
•
Set the DTE bit to 1 to enable the transfer.
3
4
Figure 8-5 Idle Mode Setup Procedure (Example)
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