HD64F2357F20V Datasheet, PDF (256/1049 Pages) Renesas Technology Corp – Hardware Manual Renesas 16-Bit Single-chip Microcomputer H8S Family / H8S/2300 Series

7.5.11 DMAC Bus Cycles (Single Address Mode)
Single Address Mode (Read): Figure 7-27 shows a transfer example in which TEND output is enabled and byte-size
single address mode transfer (read) is performed from external 8-bit, 2-state access space to an external device.
ø
Address bus
RD
DACK
TEND
DMA read
DMA read
DMA read
DMA
DMA read dead
Bus
release
Bus
release
Bus
release
Bus Last transfer Bus
release cycle
release
Figure 7-27 Example of Single Address Mode (Byte Read) Transfer
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.
ø
Address bus
RD
DACK
TEND
DMA read
DMA read
DMA read
DMA
dead
Bus
release
Bus
release
Bus
release
Last transfer
cycle
Bus
release
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 inserted 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.
Rev.6.00 Oct.28.2004 page 226 of 1016
REJ09B0138-0600H