HD6417034B RENESAS [Renesas Technology Corp], HD6417034B Datasheet - Page 149

• Manufacturer Part Number: HD6417034B
• Description: 32-Bit RISC Microcomputer
• Manufacturer: RENESAS [Renesas Technology Corp]

To prevent RTCSR from being written incorrectly, it must be written by a different method from
most other registers. A word transfer operation is used, H'69 is written in the upper byte, and the
actual data is written in the lower byte. For details, see section 8.2.11, Notes on Register Access.
8.2.9
The refresh time constant register (RTCOR) is a 16-bit read/write register that sets the compare
match cycle used with RTCNT. The values in RTCOR and RTCNT are constantly compared.
When they match, the compare match flag (CMF) is set in RTCNT and RTCSR is cleared to
H'0000. If the RFSHE bit in RCR is set to 1 when this happens, a CAS-before-RAS (CBR) refresh
is performed. When the CMIE bit in RTCSR is also set to 1, a compare match interrupt (CMI) is
generated.
Bits 15–8 are reserved and cannot be used to set the cycle. These bits are always read as 0.
RTCOR is initialized to H'00FF by a power-on reset, but is not initialized by a manual reset or in
standby mode.
To prevent RTCOR from being written incorrectly, it must be written by a different method from
most other registers. A word transfer operation is used, H'96 is written in the upper byte, and the
actual data is written in the lower byte. For details, see section 8.2.11, Notes on Register Access.
Bit
Initial value
Read/Write
Bit
Initial value
Read/Write
Bit
Initial value
Read/Write
Refresh Time Constant Register (RTCOR)
R/W
15
15
—
—
—
—
0
7
0
0
R/W
14
14
—
—
—
—
0
6
0
0
R/W
13
13
—
—
—
—
0
5
0
0
R/W
12
12
—
—
—
—
0
4
0
0
Rev. 7.00 Jan 31, 2006 page 123 of 658
Section 8 Bus State Controller (BSC)
R/W
11
11
—
—
—
—
0
3
0
0
R/W
10
10
—
—
—
—
0
2
0
0
REJ09B0272-0700
R/W
—
—
—
—
9
0
1
0
9
0
R/W
—
—
—
—
8
0
0
0
8
0