HD6417618 RENESAS [Renesas Technology Corp], HD6417618 Datasheet - Page 171

• Manufacturer Part Number: HD6417618
• Description: 32-Bit RISC Microcomputer SuperHTM RISC engine Family / SH7618 Series
• Manufacturer: RENESAS [Renesas Technology Corp]

7.4.6
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 RTCNT is written to, the upper 16 bits of the write data must
be H'A55A to cancel write protection.
Bit
2
1
0
Bit
31 to 8
7 to 0
Refresh Timer Counter (RTCNT)
Bit Name
RRC2
RRC1
RRC0
Bit Name


Initial
Value
0
0
0
Initial
Value
All 0
All 0
R/W
R/W
R/W
R/W
R/W
R
R/W
Description
Refresh Count
Specify the number of consecutive refresh cycles, when
the refresh request occurs after the coincidence of the
values of the refresh timer counter (RTCNT) and the
refresh time constant register (RTCOR). Using
consecutive refresh cycles can prolong cycles between
refreshing.
000: Once
001: Twice
010: 4 times
011: 6 times
100: 8 times
101: Reserved (setting prohibited)
110: Reserved (setting prohibited)
111: Reserved (setting prohibited)
Description
Reserved
These bits are always read as 0. The write value should
always be 0.
8-bit Counter
Rev. 6.00 Jun. 12, 2007 Page 139 of 610
Section 7 Bus State Controller (BSC)
REJ09B0131-0600