Datasheet

Section 7 DMA Controller (Not Supported in the H8S/2321)
Rev.6.00 Sep. 27, 2007 Page 292 of 1268
REJ09B0220-0600
Figure 7.28 shows a transfer example in which TEND output is enabled and word-size single
address mode transfer (read) is performed from external 8-bit, 2-state access space to an external
device.
DMA read
φ
A
ddress bus
DMA read DMA read
DMA
dead
RD
TEND
DACK
Bus
release
Bus
release
Bus
release
Bus
release
Last transfer
cycle
Figure 7.28 Example of Single Address Mode (Word Read) Transfer
A one-byte or one-word transfer is performed for one 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 (the cycle in which the transfer counter reaches 0), a one-state DMA dead
cycle is inserted after the DMA write cycle.