Datasheet

Section 7 DMA Controller (DMAC)
Rev. 3.00 Mar 17, 2006 page 313 of 926
REJ09B0283-0300
Full Address Mode (Block Transfer Mode): Figure 7.21 shows a transfer example in which
TEND output is enabled and word-size full address mode transfer (block transfer mode) is
performed from internal 16-bit, 1-state access space to external 16-bit, 2-state access space.
DMA
read
φ
Address bus
RD
LWR
TEND
HWR
Bus release Block transfer Last block transfer
DMA
write
DMA
read
DMA
write
DMA
dead
DMA
read
DMA
write
DMA
read
DMA
write
DMA
dead
Bus
release
Bus release
Figure 7.21 Example of Full Address Mode Transfer (Block Transfer Mode)
A one-block transfer is performed for a single transfer request, and after the transfer the bus is
released. While the bus is released, one or more bus cycles are executed by the CPU or DTC.
In the transfer end cycle of each block (the cycle in which the transfer counter reaches 0), a one-
state DMA dead cycle is inserted after the DMA write cycle. Even if an NMI interrupt is generated
during data transfer, block transfer operation is not affected until data transfer for one block has
ended.
DREQ
DREQDREQ
DREQ Pin Falling Edge Activation Timing: Set the DTA bit in DMABCRH to 1 for the channel
for which the DREQ pin is selected.
Figure 7.22 shows an example of normal mode transfer activated by the DREQ pin falling edge.