SH7080 Datasheet, PDF (335/1644 Pages) Renesas Technology Corp – 32-Bit RISC Microcomputer SuperH™ RISC engine Family

Section 9 Bus State Controller (BSC)
9.4.6 Refresh Timer Counter (RTCNT)
RTCNT is an 8-bit counter that increments using the clock selected by bits CKS2 to CKS0 in
RTCSR. When RTCNT matches RTCOR, RTCNT is cleared to 0. The value in RTCNT returns to
0 after counting up to 255. When writing to RTCNT, write data with setting the upper 16 bits to
H'A55A to cancel write protection.
Bit: 31
-
Initial value: 0
R/W: R/W
30
-
0
R/W
29
-
0
R/W
28
-
0
R/W
27
-
0
R/W
26
-
0
R/W
25
-
0
R/W
24
-
0
R/W
23
-
0
R/W
22
-
0
R/W
21
-
0
R/W
20
-
0
R/W
19
-
0
R/W
18
-
0
R/W
17
-
0
R/W
16
-
0
R/W
Bit: 15 14 13 12 11 10 9
8
7
6
5
4
3
2
1
0
-
-
-
-
-
-
-
-
Initial value: 0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
R/W: R
R
R
R
R
R
R
R R/W R/W R/W R/W R/W R/W R/W R/W
Bit
31 to
16
Bit Name

Initial
Value
All 0
15 to 8 
All 0
7 to 0
All 0
R/W
R/W
R
R/W
Description
Write Protect Cancellation
When writing to RTCNT, write H'A55A to these bits to
cancel write protection. These bits are always read as 0.
Reserved
These bits are always read as 0. The write value should
always be 0.
8-bit counter
Rev. 3.00 May 17, 2007 Page 277 of 1582
REJ09B0181-0300