CHAPTER 6 BUS CONTROL
User’s Manual U14272EJ3V0UM
140
6.7.3 XISACTL (0x0B00 02C4)
(1/2)
Bit
15
14
13
12
11
10
9
8
Name
Reserved
Reserved
Reserved
Reserved
Reserved
EXTRESULT
INTRESULT
EXBUFFEN
R/W
R
R
R
R
R
R/W
R/W
R/W
RTCRST
0
0
0
0
0
1
0
1
Other resets
0
0
0
0
0
1
0
1
Bit
7
6
5
4
3
2
1
0
Name
MEMWS1
MEMWS0
IOWS1
IOWS0
Reserved
Reserved
SCLKDIV1
SCLKDIV0
R/W
R/W
R/W
R/W
R/W
R
R
R/W
R/W
RTCRST
0
0
0
0
0
0
0
0
Other resets
0
0
0
0
0
0
0
0
Bit
Name
Function
15 to 11
Reserved
0 is returned when read
10
EXTRESULT
External ISA result cycle enable
0 : Disabled. The MBA bus arbiter waits until an external ISA read is finished.
1 : Enabled. The MBA bus arbiter issues a result cycle to the ISA bridge after
finishing an external ISA cycle and obtains results of the read.
Normally, set 1 to this bit.
9
INTRESULT
Internal ISA result cycle enable
0 : Disabled. The MBA bus arbiter waits until an internal ISA read is finished.
1 : Enabled. The MBA bus arbiter issues a result cycle to the ISA bridge after
finishing an internal ISA cycle and obtains results of the read.
Normally, set 1 to this bit.
8
EXBUFFEN
External buffer enable
0 : Enable external buffer control with SYSDIR and SYSEN# pins
1 : Disable external buffer control with SYSDIR and SYSEN# pins
(SYSEN# and SYSDIR pins are both forced to low level)
7, 6
MEMWS(1:0)
External ISA memory wait states (read/write strobe width)
00 : 1.5 SYSCLK cycles
01 : 2.5 SYSCLK cycles
10 : 3.5 SYSCLK cycles
11 : 4.5 SYSCLK cycles
5, 4
IOWS(1:0)
External ISA I/O wait states (read/write strobe width)
00 : 1.5 SYSCLK cycles
01 : 2.5 SYSCLK cycles
10 : 3.5 SYSCLK cycles
11 : 4.5 SYSCLK cycles
Содержание VR4181 mPD30181
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