Hitachi AP1 Data Book page 69

------------------------------------------------------HMCS45C,HMCS45CL
• Program Counter (PC)
1---64
words~
1F OF 0 7 _ 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