H8S2368 Datasheet, PDF (198/1037 Pages) Renesas Technology Corp – Renesas 16-Bit Single-Chip Microcomputer H8S Family/H8S/2300 Series

Section 6 Bus Controller (BSC)
6.3.11 Refresh Timer Counter (RTCNT)
RTCNT is an 8-bit readable/writable up-counter. RTCNT counts up using the internal clock
selected by bits RTCK2 to RTCK0 in REFCR.
When RTCNT matches RTCOR (compare match), the CMF flag in REFCR is set to 1 and
RTCNT is cleared to H'00. If the RFSHE bit in REFCR is set to 1 at this time, a refresh cycle is
started. If the RFSHE bit is cleared to 0 and the CMIE bit in REFCR is set to 1, a compare match
interrupt (CMI) is generated.
RTCNT is initialized to H'00 by a reset and in hardware standby mode. It is not initialized in
software standby mode.
6.3.12 Refresh Time Constant Register (RTCOR)
RTCOR is an 8-bit readable/writable register that sets the period for compare match operations
with RTCNT.
The values of RTCOR and RTCNT are constantly compared, and if they match, the CMF flag in
REFCR is set to 1 and RTCNT is cleared to H'00.
RTCOR is initialized to H'FF by a reset and in hardware standby mode. It is not initialized in
software standby mode.
6.4 Operation
6.4.1 Area Division
The bus controller divides the 16-Mbyte address space into eight areas, 0 to 7, in 2-Mbyte units,
and performs bus control for external address space in area units. Chip select signals (CS0 to CS7)
can be output for each area. Figure 6.5 shows an outline of the memory map.
Rev. 5.00 Aug 02, 2006 page 144 of 980
REJ09B0050-0500