--------------------------------------------------------HMCS44C,HMCS44CL
• Program
Counter
(PC)
!---64
words------!
1F
OF
07_
3D
3E
3F
(Hexa-decimal)
ftJi
0
ri
1
2
Program Area
30
ri
31
1--64
words-----l
page
page
page
(
page
page
Timer/counter
Interrupt Address (0 page
3F
address)
Input Interrupt Address(1 page 3F address)
Reset Address
(31
page 3F address)
1 F
OF
07
_ 3D
3E
3F
(Hexa-decimal)
Pattern Area
Pattern Area
61
page
62
page
Figure
1
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
OB
19 13
61
30
23
17
38
26
59
3B
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
1B
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
2B
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
45
To Next Page
Loading...
