Section 12 Bus State Controller (BSC)
• Refresh timer control/status register (RTCSR)
• Refresh timer counter (RTCNT)
• Refresh time constant register (RTCOR)
• Reset wait counter (RWTCNT)
12.4.1
Common Control Register (CMNCR)
CMNCR is a 32-bit register that controls the common items for each area. This register is only
initialized by a power-on reset, and it is not initialized by a manual reset and in the standby mode.
Do not access external memory other than area 0 until the CMNCR register initialization is
complete.
Bit
Bit Name
31 to 16
15
WAITSEL
14, 13
12
MAP
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REJ09B0023-0400
Initial
Value
R/W
Description
All 0
R
Reserved
These bits are always read as 0. The write value
should always be 0.
0
R/W
WAIT Signal Sampling Timing Specification
Specifies the external WAIT signal sampling timing.
0: Samples the WAIT signal at the falling edge of the
1: Samples the WAIT signal at the rising edge of the
All 0
R
Reserved
These bits are always read as 0. The write value
should always be 0.
0
R/W
Space Specification
Selects the address map for the external address
space. The address maps to be selected are shown in
tables 12.2 and 12.3.
0: Selects address map 1.
1: Selects address map 2.
CKIO. In this case, the WAIT signal can be input
asynchronously.
CKIO. In this case, the WAIT signal must be input
synchronously.