Figure 7.20 Example Of Full Address Mode Transfer (Burst Mode) - Renesas H8S/2368 Series Hardware Manual

Address bus
Bus release

Figure 7.20 Example of Full Address Mode Transfer (Burst Mode)

In burst mode, one-byte or one-word transfers are executed consecutively until transfer ends.
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.
If a request from another higher-priority channel is generated after burst transfer starts, that
channel has to wait until the burst transfer ends.
If an NMI interrupt is generated while a channel designated for burst transfer is in the transfer
enabled state, the DTME bit in DMABCRL is cleared and the channel is placed in the transfer
disabled state. If burst transfer has already been activated inside the DMAC, the bus is released on
completion of a one-byte or one-word transfer within the burst transfer, and burst transfer is
suspended. If the last transfer cycle of the burst transfer has already been activated inside the
DMAC, execution continues to the end of the transfer even if the DTME bit is cleared.
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.
Rev. 2.00, 05/03, page 252 of 820
DMA DMA DMA
read write read
DMA DMA
write read
Last transfer cycle
Burst transfer
DMA DMA
write dead
Bus release