ZiLOG System 8000

HRM
Zilog
HRM
Table 4-2
ZBI
status
Lines, Transaction
Coding:
S4
S3
S2
S1
SO
TRANSACTION
0 0
0
0 0
Internal operation
0
0
0
0
1
Memory refresh
0
0
0
1
0
I/O reference
0
0
0 1
1
Special
I/O reference
0 0
1 0
0
Segment trap acknowledge
0
0
1
0
1
INT 1
Interrupt acknowledge
0
0
1
1
0
INT
3
Interrupt acknowledge
0
0
1
1
1 INT
2
Interrupt acknowledge
0
1 0 0
0
Data memory request
0 1
0 0
1
Stack memory request
0
1
0
1 0
Transfer between data memory and an
EPU
0
1
0
1
1
Transfer between
stack memor'y
and
an
EPU
0
1
1 0 0
Program reference,
nth cycle~
0 1
1 0 1
Program reference,
1 st c yc Ie
0
1 1
1
0
Transfer between
CPU and
EPU
0 1
1 1 1
Reserved
1
X
X
X
X
Reserved
Table 11-3 Data Width Codes: Byte, Word, and Long Word
B/W\
W/LW
DATA WIDTH
Sets
the'
data width to byte
width,
8
bits,
data on lines
AD<7:0>
0
Sets data
width
to
word
size,
16
bits,
data
on
lines
AD<15:0>
0
Sets data width to
double-word
size,
3
r
,
bits,
data on lines
c..
AD<31 : 0)-
0
0
Reservec,
4-8
Zilog
. 4-8