Datasheet

Section 6 Bus Controller (BSC)
Page 184 of 1408 R01UH0309EJ0500 Rev. 5.00
Sep 24, 2012
H8S/2456, H8S/2456R, H8S/2454 Group
6.3.11 Refresh Control Register (REFCR)
REFCR specifies DRAM/synchronous DRAM interface refresh control.
Note: The synchronous DRAM interface is not supported by the H8S/2456 Group and H8S/2454
Group.
Bit Bit Name Initial Value R/W Description
15 CMF 0 R/(W)
*
Compare Match Flag
Status flag that indicates a match between the
values of RTCNT and RTCOR.
[Clearing conditions]
• When 0 is written to CMF after reading CMF =
1 while the RFSHE bit is cleared to 0
• When CBR refreshing is executed while the
RFSHE bit is set to 1
[Setting condition]
When RTCOR = RTCNT
14 CMIE 0 R/W Compare Match Interrupt Enable
Enables or disables interrupt requests (CMI) by
the CMF flag when the CMF flag is set to 1.
This bit is valid when refresh control is not
performed. When the refresh control is performed,
this bit is always cleared to 0 and cannot be
modified.
0: Interrupt request by CMF flag disabled
1: Interrupt request by CMF flag enabled
13
12
RCW1
RCW0
0
0
R/W
R/W
CAS-RAS Wait Control
These bits select the number of wait cycles to be
inserted between the CAS assert cycle and RAS
assert cycle in a DRAM/synchronous DRAM
refresh cycle.
00: Wait state not inserted
01: 1 wait state inserted
10: 2 wait states inserted
11: 3 wait states inserted
Note: * Only 0 can be written, to clear the flag.