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Chapter 14 Automatic Transfer Controller
Operation
XIV - 32
14-3-19 Transfer Mode E
Transfer mode E is a burst mode. In this mode, when ATC1 is activated, it automatically transfers the
number of data bytes set in the transfer data counter (AT1TRC) in one continuous operation.
AT1MAP0
AT1MAP0 + 1
AT1MAP0 + 2
AT1MAP0 + 3
Memory Pointer 0
00000 - 3FFFF
AT1MAP1
AT1MAP1 + 1
AT1MAP1 + 2
A1TMAP1 + 3
Memory Pointer 1
00000 - 3FFFF
(1)
(3)
(5)
·
·
·
·
·
(2)
(4)
(6)
(2)
(4)
(6)
Set the source address in 18-bit memory pointer 0 (AT1MAP0H, M, L), and set the destination address
in 18-bit memory pointer 1 (AT1MAP1H, M, L). Once ATC1 is activated, memory pointers 0 and 1
increment by one each a byte-length data transfer ends.
For burst transfers, set the number of data bytes to be transferred in the transfer data counter
(AT1TRC). The counter can be set to a maximum of 255 bytes. Once the burst transfer starts, the
counter decrements each time ATC1 transfers one byte of data. When it reaches x'00', an interrupt
(ATC1IRQ) occurs and the burst transfer ends.
It is possible to shut down ATC1 during burst transfers using external interrupt 0. You can enable or
disable ATC1 shutdown with the burst transfer stop enable flag (BSTP) of ATC1 control register 1
(AT1CNT1). When BTSTP=1 and the interrupt request flag for external interrupt 0 (the IRQ0IR flag in the
IRQ0ICR register) is set, the ATC1 data transfer shuts down immediately. During this shutdown, the
transfer counter and the memory pointers save the values they contained prior to the shutdown. When
the interrupt service routine ends and a new ATC1 trigger factor occurs, the burst transfer restarts from
the point at which it stopped.
Figure 14-3-16 Transfer Mode E