SH7730 Datasheet, PDF (446/1188 Pages) Renesas Technology Corp – Renesas 32-Bit RISC Microcomputer SuperHTM RISC engine Family / SH7780 Series

Section 11 Bus State Controller (BSC)
11.5.9 Wait between Access Cycles
As the operating frequency of LSIs becomes higher, the off-operation of the data buffer often
collides with the next data access when the read operation from devices with slow access speed is
completed. As a result of these collisions, the reliability of the device is low and malfunctions may
occur. This LSI has a function that avoids data collisions by inserting wait cycles between
continuous access cycles.
The number of wait cycles between access cycles can be set by bits IWW[2:0], IWRWD[2:0],
IWRWS[2:0], IWRRD[2:0], and IWRRS[2:0] in CSnBCR. The conditions for setting the wait
cycles between access cycles (idle cycles) are shown below.
1. Continuous accesses are write-read or write-write
2. Continuous accesses are read-write for different spaces
3. Continuous accesses are read-write for the same space
4. Continuous accesses are read-read for different spaces
5. Continuous accesses are read-read for the same space
Rev. 1.00 Sep. 19, 2007 Page 398 of 1136
REJ09B0359-0100