Fujitsu MB96300 series Hardware Manual page 328

CHAPTER 12 EXTERNAL BUS INTERFACE
10.0000
H
reset vector fetch, except on MB96(F)38x at external Boot Vector fetch in non-multiplexed bus mode, where
external area 4 and CS4 are used. The value of EAS[5:2] can be changed by Software at any time.
Table 12.2-4 Initial values of EAS[5:2]
External
External
Area 2
External
Area 3
External
Area 4
External
Area 5
■ Operation of the External address area selection
When the CPU accesses program or data, an external bus access is performed if a match between the upper 8
bits of an address and any EAS[5:2] setting is detected (the corresponding External area must be activated in
the EBM register). Depending on the setting of the corresponding EASZ[2:0] bits of the EACH register, a
certain number of LSB bits of the EAS register is ignored, and decoding becomes possible for an area from
64 KB to 8 MB.
Examples:
EAS2= F0
EACH2: EASZ = "000"
- not decoded banks: 00...EF, F1-FF
- decoded banks: F0
EAS2= F0
EACH2: EASZ = "001"
- not decoded banks: 00...EF, F2-FF
- decoded banks: F0, F1
EAS2= 17
EACH2: EASZ = "000"
- not decoded banks: 00...16, 18-FF
- decoded banks: 17
320
in 4 sections. The external area 5 and the corresponding Chip select CS5 is used during external
Initial value of
area EAS register
EAS2= 00
H
(EACH2: EASZ = "110")
EAS3= 40
H
(EACH3: EASZ = "110")
MB96(F)38x at external
Boot Vector fetch in non-
multiplexed bus mode:
EAS4= 80
H
(EACH4: EASZ = "111")
all other devices and modes:
EAS4= 80
H
(EACH4: EASZ = "110")
EAS5= C0
H
(EACH5: EASZ = "110")
H
H
H
MB96300 Super Series Hardware Manual
Default Memory area
h'10.0000...h'3f.ffff (3MByte)
h'40.0000...h'7f.ffff (4MByte)
h'80.0000...h'ff.ffff (8MByte
incl. external Reset vector)
h'80.0000...h'bf.ffff (4MByte)
h'c0.0000...h'ff.ffff
(=4MByte incl. external Reset
vector)
Chip select
signal
CS2
CS3
CS4
CS5