Chain Transfer; Figure 7.8 Chain Transfer Operation - Renesas H8S/2158 User Manual

Section 7 Data Transfer Controller (DTC)
7.5.4

Chain Transfer

Setting the CHNE bit in MRB to 1 enables a number of data transfers to be performed
consecutively in response to a single transfer request. SAR, DAR, CRA, CRB, MRA, and MRB,
which define data transfers, can be set independently.
Figure 7.8 shows the overview of chain transfer operation. When activated, the DTC reads the
register information start address stored at the DTC vector address, and then reads the first register
information at that start address. After the data transfer, the CHNE bit will be tested. When it has
been set to 1, DTC reads the next register information located in a consecutive area and performs
the data transfer. These sequences are repeated until the CHNE bit is cleared to 0.
In the case of transfer with the CHNE bit set to 1, an interrupt request to the CPU is not generated
at the end of the specified number of transfers or by setting of the DISEL bit to 1, and the interrupt
source flag for the activation source is not affected.
DTC vector
Register information
address
Rev. 3.00 Jan 25, 2006 page 160 of 872
REJ09B0286-0300
start address

Figure 7.8 Chain Transfer Operation

Register information
CHNE = 1
Register information
CHNE = 0
Source
Destination
Source
Destination