Data Sheet U14360EJ1V0DS00
μ
PD17230, 17231, 17232, 17233, 17234, 17235, 17236
17
2.3
Stack
A stack is a register to save a program return address and the contents of system registers (to be described later)
when a subroutine is called or when an interrupt is accepted.
2.3.1
Stack configuration
Figure 2-5 shows the stack configurarion.
A stack consists of a stack pointer (a 4-bit binary counter, the high-order 1 bit fixed to 0), five 11-bit (
μ
PD17230)/
12-bit (
μ
PD17231)/13-bit (
μ
PD17232, 17233)/14-bit (
μ
PD17234, 17235, 17236) address stack registers, and three
6-bit interrupt stack registers.
Figure 2-5. Stack Configuration
Address stack registers
(ASR)
b
11
b
10
b
9
b
8
b
7
b
6
b
5
b
4
b
3
b
2
b
1
b
0
Address stack register 1
Address stack register 2
Address stack register 3
Address stack register 4
b
2
b
1
b
0
SPb
2
SPb
1
SPb
0
Stack pointer
(SP)
0H
1H
2H
3H
4H
5H
6H
7H
0H
1H
2H
Interrupt stack registers
(INTSK)
BANKSK1
BANKSK2
BCDSK0
BCDSK1
BCDSK2
CMPSK0
CMPSK1
CMPSK2
CYSK0
CYSK1
CYSK2
ZSK0
ZSK1
ZSK2
IXESK0
IXESK1
IXESK2
Address stack register 0
The RESET pin is
internally pulled down
and reset is effected.
b
3
0
b
12
PD17231
μ
PD17232, 17233
μ
PD17234, 17235, 17236
μ
b
4
b
3
b
2
b
5
BANKSK0
b
1
b
0
Undefined
Undefined
Undefined
b
13
PD17230
μ