275
Bus and Memory Control (BCU, MEMC)
Chapter 7
Preliminary User’s Manual U17566EE1V2UM00
(5)
BCC - Bus cycle control register
The 16-bit BCC register controls the number of idle states inserted after the T2
cycle. Each chip select area is controlled separately. A maximum of three idle
states is possible.
Idle states can be inserted when accessing SRAM , external I/O, external
ROM, or page ROM.
Access
This register can be read/written in 16-bit units.
Address
FFFF F488
H
Initial Value
FFFF
H
. After system reset, three idle states are inserted.
Note
For access to internal memory, no idle states are inserted.
Caution
To initialize an external memory area after a reset, this register has to be set.
Do not access external devices before initialization is finished. Do not change
this register while an external device is accessed.
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
BC71 BC70 BC61 BC60 BC51 BC50 BC41 BC40 BC31 BC30 BC21 BC20 BC11 BC10 BC01 BC00
CS7
CS6
CS5
CS4
CS3
CS2
CS1
CS0
Table 7-22
BCC register contents
Bit position
Bit name
Function
15 to 0
BCk[1:0]
Sets the number of idle states for each chip select area.
BCk[1:0]
Inserted idle states
00
B
No idle state inserted
01
B
1 idle state
10
B
2 idle states
11
B
3 idle states
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