m30833fjgp Renesas Electronics Corporation., m30833fjgp Datasheet - Page 79

• Manufacturer Part Number: m30833fjgp
• Description: Renesas 16/32-bit Single-chip Microcomputer M16c Family / M32c/80 Series
• Manufacturer: Renesas Electronics Corporation.

R
R
M
e
E
3
. v
J
2
Figure 7.2 Address Bus and Chip-Select Signal Outputs (Separate bus)
0
C
1
9
3 .
B
8 /
Chip-Select Signal
0
1
3
Chip-Select Signal
Chip-Select Signal
0
3
J
G
Example 3:
4
a
Example 1:
Address Bus
o r
0 -
n
Address Bus
When the microcomputer accesses the external
space j specified by another chip-select signal in the
next cycle after having accessed the external space i,
both address bus and chip-select signal change.
3 .
1
u
When the microcomputer accesses the space i
specified by the same chip-select signal in the next
cycle after having accessed the external space i,
the address bus changes but the chip-select signal
does not.
Data Bus
NOTES:
i = 0 to 3
j = 0 to 3, excluding i
(See Figure 6.3 for i, j and p, k)
i = 0 to 3
(See Figure 6.3 for i and k)
, 1
3
p
Data Bus
1
1. The above applies to the address bus and chip-select signal in two consecutive cycles.
(
2
M
CSk
0
0
CSk
CSp
3
By combining these examples, a chip-select signal extended by two or more cycles may be output.
6
2
C
8 /
Page 56
, 3
M
3
2
Address
Access
External
Space i
C
Address
f o
Access
External
Space i
k = 0 to 3
p= 0 to 3, excluding k
k = 0 to 3
8 /
4
Data
3
8
Data
) T
8
Access
External
Space i
Access
External
Space j
Data
Data
Example 4:
Chip-Select Signal
Example 2:
Chip-Select Signal
When the microcomputer accesses the SFR or the
internal ROM/RAM area in the next cycle after
having accessed an external space, the chip-select
signal changes but the address bus does not.
When the microcomputer does not access any
space in the next cycle after having accessed an
external space (no pre-fetch of an instruction is
generated), neither address bus nor chip-select
signal changes.
Address Bus
Address Bus
Data Bus
Data Bus
CSk
CSk
k = 0 to 3
k = 0 to 3
Access
External
Space
Access
External
Space
Address
Address
Data
Data
No Access
Access SFR,
Internal
ROM/RAM
Area
7. Bus