SH7709S Datasheet, PDF (417/807 Pages) Renesas Technology Corp – Renesas 32-Bit RISC Microcomputer Super RISC engine Family/SH7700 Series

CK
Internal
address bus
Internal
data bus
SAR2 DAR2 SAR2+2 DAR2 SAR2+4 DAR2 SAR2+6 DAR2 SAR2
SAR2 data
SAR2+2 data
SAR2+4 data
SAR2+6 data
First transfer on
channel 2
SAR2 output
DAR2 output
Second transfer
SAR2+2 output
DAR2 output
Third transfer
SAR2+4 output
DAR2 output
Fourth transfer Fifth transfer
SAR2+6 output
DAR2 output
SAR2 reload
SAR2 output
DAR2 output
Figure 11.23 Timing Chart of Source Address Reload Function
The reload function can be executed with a transfer data size of 8, 16, or 32 bits.
DMATCR2, which specifies the transfer count, decrements 1 each time a transfer ends regardless
of whether the reload function is on or off. Consequently, a multiple of four must be specified in
DMATCR2 when the reload function is on. Operation is not guaranteed if other values are
specified.
The counter that counts the execution of four transfers for the address reload function is reset by
clearing the DME bit in DMAOR or the DE bit in CHCR2, by setting the transfer end flag (TE bit
in CHCR2), by DMAC address error, and by NMI input, as well as by a reset, but the SAR2,
DAR2, and DMATCR2 registers are not reset. Therefore, if these sources are generated, there will
be a mix of an initialized counter and uninitialized registers in the DMAC, and a malfunction will
be caused by restarting the DMAC in that state. Consequently, if one of these sources other than
setting of the TE bit occurs during use of the address reload function, set SAR2, DAR2, and
DMATCR2 again.
Rev. 5.00, 09/03, page 373 of 760