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MAR specifies the start address of the transfer source or transfer destination as 24 bits. MAR is
incremented or decremented by 1 or 2 each time a byte or word is transferred.
IOAR specifies the lower 16 bits of the other address. The 8 bits above IOAR have a value of
H'FF.
Figure 8-3 illustrates operation in sequential mode.
Address T
Address B
The number of transfers is specified as 16 bits in ETCR. ETCR is decremented by 1 each time a
transfer is executed, and when its value reaches H'0000, the DTE bit is cleared and transfer ends.
If the DTIE bit is set to 1 at this time, an interrupt request is sent to the CPU or DTC.
The maximum number of transfers, when H'0000 is set in ETCR, is 65,536.
Figure 8-3 Operation in Sequential Mode
Transfer
1 byte or word transfer performed in
response to 1 transfer request
Legend
Address T = L
DTID
Address B = L + (–1)
Where : L = Value set in MAR
N = Value set in ETCR
IOAR
DTSZ
· (2
· (N–1))
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