SH7713 Datasheet, PDF (471/904 Pages) Renesas Technology Corp – Renesas 32-Bit RISC Microcomputer SuperHTM RISC engine Family / SH7700 Series

Section 12 Bus State Controller (BSC)
Self-refresh timing is shown in figure 12.26. Settings must be made so that self-refresh
clearing and data retention are performed correctly, and auto-refreshing is performed at the
correct intervals. When self-refreshing is activated from the state in which auto-refreshing is
set, or when exiting standby mode other than through a power-on reset, auto-refreshing is
restarted if the RFSH bit is set to 1 and the RMODE bit is cleared to 0 when self-refresh mode
is cleared. If the transition from clearing of self-refresh mode to the start of auto-refreshing
takes time, this time should be taken into consideration when setting the initial value of
RTCNT. Making the RTCNT value 1 less than the RTCOR value will enable refreshing to be
started immediately.
After self-refreshing has been set, the self-refresh state continues even if the chip standby state
is entered using the LSI standby function, and is maintained even after recovery from standby
mode by an interrupt.
The self-refresh state is not cleared by a manual reset.
In case of a power-on reset, the bus state controller’s registers are initialized, and therefore the
self-refresh state is cleared.
Rev.1.50 Aug. 30, 2006 Page 431 of 860
REJ09B0288-0150