------------------------------------------------------HMCS45C,HMCS45CL
• Program Counter
(PC)
1---64
words~
1F
OF
07_
3D
3E
3F (Hexa-decimal)
JJ
0
JJi
1
2
Program Area
30
page
page
page
(
I
page
Timer/counter
Interrupt Address
(0
page 3F address)
Input Interrupt Address
(1
page 3F address)
fji
31
page
1---64
words---f
Reset Address
(31
page 3F address)
1 F
OF
07
_ 3D
3E
3F (Hexa-decimal)
Pattern Area
61
page
Pattern Area
62
page
Figure
ROM
Address Space
The program counter
is
used
for
addressing of
ROM.
It
con-
sists
of
the
page
part and the address part
as
shown
in
Figure
2.
Once a certain value
is
loaded into a
page
part, the content
is
unchanged until other value
is
loaded
by
the program. The setta-
ble
value
of
a
page
part
is
any number between 0 to
31.
Page Part
~---
Address Part
---
.....
PCe
Figure
2 Configuration
of
Program Counter
The address part
is
a 6-bit polynomial counter and counts
up
for
each instruction
cycle
time. The sequence
in
the decimal and
hexa-decimal system
is
shown
in
Table
1.
This sequence
is
cir-
culating and has neither the starting nor ending point.
It
doesn't
generate an overflow carry. Consequently, the program on a
same page
is
executed
in
order unless the value
of
the
page
part
is
changed.
Table
1 Program Counter Address Part Sequence
Decimal
Hexadecimal
Decimal
Hexadecimal
Decimal
Hexadecimal
63
3F
5 05 9
09
62
3E
11
08
19
13
61
3D
23
17
38
26
59
38
46
2E
12
OC
55 37 28
1C
25
19
47
2F
56
38
50
32
30
1E
49
31
37
25
60
3C
35
23
10
OA
57
39
6
06
21
15
51
33
13
00
42
2A
39
27 27
18
20
14
14
OE
54
36
40
28
29
10
45
20
16
10
58
3A
26
1A
32
20
53
35
52
34
0
00
43
28
41
29
1
01
22 16
18
12
3
03
44
2C
36
24
7
07
24
18
8
08 15
OF
48
30
17
11
31
1F
33
21
34
22
2
02
4
04
67
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