m30833fjgp Renesas Electronics Corporation., m30833fjgp Datasheet - Page 75

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

R
R
M
7. Bus
7.1 Bus Settings
e
E
3
. v
J
Table 7.1 Bus Settings
Figure 7.1 DS Register
2
0
Selecting external address bus width
Setting bus width after reset
Switching between separate bus or multiplexed bus
Number of chip-select
_________ _______ __________
In memory expansion mode or microprocessor mode, some pins function as bus control pins to input and
output data from external devices. A
WRH/BHE/CASH, RD/DW, BCLK/ALE, HLDA/ALE, HOLD, ALE/RAS, and RDY are used as bus control
pins.
C
1
9
3 .
B
8 /
Bus control pins in M32C/83T cannot be used.
The BYTE pin, the DS register, the PM05 to PM04 bits in the PM0 register and the PM11 to PM10 bits in
the PM1 register determine bus settings.
Table 7.1 lists how to change a bus setting. Figure 7.1 shows the DS register.
0
1
3
NOTE
0
3
J
G
4
a
o r
0 -
n
External Data Bus Width Control Register
b7
3 .
1
u
NOTES:
, 1
3
p
b6
1
(
1. After reset, the DS3 bit is set to "1" when the BYTE pin is held "L". It is set to "0" when the BYTE pin
2. The DS register in the M32C/83T cannot be used.
2
M
0
b5
is held "H".
0
3
6
2
b4
C
_____ ______
8 /
b3
Page 52
, 3
Bus Setting
b2
M
b1
3
2
C
b0
f o
8 /
4
3
(b7 - b4)
Symbol
8
) T
8
DS0
DS1
DS3
DS2
Bit
Symbol
DS
0
to A
External Space 0 Data
Bus Width Select Bit
External Space 1 Data
Bus Width Select Bit
External Space 3 Data
Bus Width Select Bit
Nothing is assigned. When write, set to "0".
When read, its content is indeterminate.
External Space 2 Data
Bus Width Select Bit
_________
22
, A
______
Bit Name
23
, D
Address
000B
0
_________
16
to D
(1)
15
DS register
BYTE pin (external space 3 only)
PM05 to PM04 bits in PM0 register
PM11 to PM10 bits in PM1 register
, MA
(2)
0 : 8 bits wide
1 : 16 bits wide
0 : 8 bits wide
1 : 16 bits wide
0 : 8 bits wide
1 : 16 bits wide
0 : 8 bits wide
1 : 16 bits wide
0
_______
to MA
After Reset
XXXX 1000
XXXX 0000
12
Function
, CS
Changed By
_______
_______
0
2
2
to CS
(BYTE pin = "L")
(BYTE pin = "H")
_______
3
, WRL/WR/CASL,
________ ______ _________
RW
RW
RW
RW
RW
7. Bus