r4f2426 Renesas Electronics Corporation., r4f2426 Datasheet - Page 207

• Manufacturer Part Number: r4f2426
• Description: 16-bit Single-chip Microcomputer H8s Family / H8s/2400 Series
• Manufacturer: Renesas Electronics Corporation.

Bit
11
10
9
8
7
6
Bit Name
—
RTCK2
RTCK1
RTCK0
RFSHE
CBRM
Initial Value
0
0
0
0
0
0
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Description
Reserved
This bit can be read from or written to. However,
the write value should always be 0.
Refresh Counter Clock Select
These bits select the clock to be used to
increment the refresh counter. When the input
clock is selected with bits RTCK2 to RTCK0, the
refresh counter begins counting up.
000: Count operation halted
001: Count on φ/2
010: Count on φ/8
011: Count on φ/32
100: Count on φ/128
101: Count on φ/512
110: Count on φ/2048
111: Count on φ/4096
Refresh Control
Refresh control can be performed. When refresh
control is not performed, the refresh timer can be
used as an interval timer.
0: Refresh control is not performed
1: Refresh control is performed
CBR Refresh Mode
Selects CBR refreshing performed in parallel with
other external accesses, or execution of CBR
refreshing alone.
When the continuous synchronous DRAM space
is set, this bit can be read/written, but the setting
contents do not affect operations.
0: External access during CAS-before-RAS
1: External access during CAS-before-RAS
refreshing is enabled
refreshing is disabled
Rev. 1.00 Sep. 19, 2008 Page 179 of 1270
Section 6 Bus Controller (BSC)
REJ09B0466-0100