Datasheet

Section 6 Bus Controller (BSC)
R01UH0309EJ0500 Rev. 5.00 Page 251 of 1408
Sep 24, 2012
H8S/2456, H8S/2456R, H8S/2454 Group
(3) Refreshing and All-Module-Clocks-Stopped Mode
In this LSI, if the ACSE bit is set to 1 in MSTPCRH, and then a SLEEP instruction is executed
with the setting for all peripheral module clocks to be stopped (MSTPCR = H'FFFF, EXMSTPCR
= H'FFFF) or for operation of the 8-bit timer module alone (MSTPCR = H'FFFE, EXMSTPCR =
H'FFFF), and a transition is made to the sleep state, the all-module-clocks-stopped mode is
entered, in which the bus controller and I/O port clocks are also stopped. As the bus controller
clock is also stopped in this mode, CBR refreshing is not executed. If DRAM is connected
externally and DRAM data is to be retained in sleep mode, the ACSE bit must be cleared to 0 in
MSTPCRH.