HMCS404AC------------------------------------------------------------------------
bit
3
bit 2 bit 1
bit
0
IMO
IFO
RSP
I/E
(1M
of
INTo)
(IF
of
INTo)
(Reset
SP
Bit)
(Interrupt Enable
Flag)
o
$000
IMTA
IFTA IM1
IF1
(1M
of
TIMER-A)
(IF
of
TIMER-A)
(1M
of
INTI)
(IF
of
INTI)
$001
Not
Used Not Used
IMTB IFTB
(1M
of
TIMER-B)
(IF
of
TIMER
-B)
2
$002
Not
Used Not Used
IMS
IFS
(1M
of
SERIAL)
(IF
of
SERIAL)
3
$003
IF Interrupt Request Flag
1M
Interrupt
Mask
lIE
Interrupt Enable Flag
SP
Stack Pointer
(Note)
~ach
bi~
in Inte.rrupt Control Bits Area!s
set
b~
SEM/SEMO instruction,
is
reset
by
REM/REMO instruction
and
is
tested by
TM/TMO
Instruction.
It
IS
not
affected by other instructions. Furthermore, Interrupt Request
Flag
is
not
affected by SEM/SEMO instruction.
The content
of
Status
becomes
invarid when
"Not
Used"
bit
is
tested.
Fig.3
Configuration
of
Interrupt Control
Bit
Area
• Interrupt Control Bit Area .....
$000
to
$003
This area
is
used for interrupt controls, and
is
illustrated in
Fig.3. It,is accessable
only by
RAM
bit manipulation instruction.
However, the interrupt request flag cannot be set by software.
• Special Register Area .....
$004
to
$OOB
Special Register
is
a mode
or
a data register for the external
interrupt, the serial interface, and the timer/counter. These
registers are classified into 3 types: Write-only, Read-only, and
Read/Write
as
shown in Fig.
2.
These registers cannot be
accessed by
RAM
bit manipulation instruction.
Memory
Registers
Stack Area
MR(O)
$
020
960
Level
16
$3CO
MR(l)
$
021
Level
15
MR(2)
$
022
Level
14
MR(3)
$
023
Level
13
MR(4)
$
024
Level
12
MR(5)
$
025
Level
11
MR(6)
$
026
Level
10
MR(7)
$
027
Level
9
MR(8)
$
028
Level
8
• Data Area .....
$020
to
$ODF
16 digits
of
$020 to $02F are called memory register (MR)
and accessable by LAMR and XMRA instructions.
• Stack Area ....
$leo
to
$lFF
Stack Area
is
used for LIFO stacks with the contents
of
the
program counter (PC), status (ST) and carry (CA) when process-
ing subroutine call and interrupt.
As
1 level requires 4 digits,
this stack area
is
nested to 16 level-stack max. The data pushed
in the stack and
UFO
stack state are provided in Fig. 4. The
program counter is restored by RTN and RTNI instructions.
Status and
Carry are restored only by RTNI instruction. The
area, not used for stacking,
is
available
as
a data area.
bit3 bit2
bitl
bitO
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
MR(9)
MR(10)
MR(ll)
MR(12)
MR(13)
MR(14)
$
029
Level
$
02A
Level
$
026
Level
$
02C
Level
$
020
Level
$
02E
Level
7V
6 1
5
4
3 1
2
1
PC"
$3FC
PC
10
PC
7
$ 3FD
CA
PC
4
$ 3FE
PC;
--;;c;-
~
$3FF
023
MR(15) $
02F
1023
Level
PC13
to
PCo
; Program Counter
ST; Status
CA; Carry
1 $ 3FF
PC,
Fig. 4 Configuration
of
Memory Register, Stack Area and Stack Position
308
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