98 HITACHI
Bit 14: IOE
Description
0
Area 6 is external memory space (initial value)
1
Area 6 is an address/data multiplexed I/O area
Bit 13 (warp mode bit (WARP)): WARP selects warp or normal mode. 0 sets it for normal
mode and 1 sets it for warp mode. In warp mode, some external accesses are carried out in
parallel with internal access.
Bit 13: WARP
Description
0
Normal mode: External and internal accesses are not simultaneously
performed (initial value)
1
Warp mode: External and internal accesses are simultaneously
performed
Bit 12 (RD duty (RDDTY)): RDDTY selects 35% or 50% of the T1 state as the high-level duty
cycle ratio of signal
RD
. 0 sets it for 50%, 1 sets it for 35%. Only set to 1 when the operating
frequency is a minimum of 10 MHz.
Bit 12: RDDTY
Description
RD
signal high-level duty cycle is 50% of T1 state (initial value)
RD
signal high-level duty cycle is 35% of T1 state
0
1
Bit 11 (byte access select (BAS)): BAS selects whether byte access control signals are
WRH
,
WRL
, and A0, or
LBS
,
WR
and
HBS
during word space accesses. When this bit is cleared to
0,
WRH
,
WRL
, and A0 signals are valid; when set to 1,
LBS
,
WR
, and
HBS
, signals are valid.
Bit 11: BAS
Description
WRH
,
WRL
, and A0 enabled (initial value)
LBS
,
WR
, and
HBS
enabled
0
1
Bits 10–0 (reserved): These bits always read as 0. The write value should always be 0.
8.2.2
Wait State Control Register 1 (WCR1)
Wait state control register 1 is a 16-bit read/write register that controls the number of states for
accessing each area and the whether wait states are used. WCR1 is initialized to H'FFFF by a
power-on reset. It is not initialized by a manual reset or by the standby mode.