r4f2456 Renesas Electronics Corporation., r4f2456 Datasheet - Page 271

• Manufacturer Part Number: r4f2456
• Description: 16-bit Single-chip Microcomputer H8s Family / H8s/2400 Series
• Manufacturer: Renesas Electronics Corporation.

(3)
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.
φ
Address bus
RASn (CSn)
UCAS, LCAS
OE (RD)
WR (HWR)
Data bus
Note: n = 2 to 5
Figure 6.52 Example of Timing when Precharge Time after Self-Refreshing Is Extended
Refreshing and All-Module-Clocks-Stopped Mode
Software
standby
TR
c3
by 2 States
TR
p1
TR
p2
Rev. 1.00 Sep. 19, 2008 Page 241 of 1342
T
p
DRAM space write
Section 6 Bus Controller (BSC)
T
r
T
c1
REJ09B0467-0100
T
c2