UPD17073 NEC, UPD17073 Datasheet - Page 24

• Manufacturer Part Number: UPD17073
• Description: 4-BIT SINGLE-CHIP MICROCONTROLLER WITH HARDWARE FOR DIGITAL TUNING SYSTEM
• Manufacturer: NEC

3.3 Stack Pointer (SP)
24
Figure 3-3 shows the configuration and functions of the stack pointer.
The stack pointer is a 4-bit binary counter.
The stack pointer specifies the addresses of the address stack registers.
The value of the stack pointer can be directly read or written by using a register manipulation instruction.
reset
At
Power-ON
Clock stop
CE
Stack pointer
Name
SP
Figure 3-3. Configuration and Functions of Stack Pointer
b
0
0
3
Flag symbol
b
0
0
2
b
0
0
1
S
P
1
1
1
1
1
b
0
1
0
0
0
0
S
P
0
0
Address 0 (ASR0)
Address 1 (ASR1)
Address 2 (ASR2)
Fixed to "0"
Address
01H
Specifies address of address stack register (ASR)
Read/
Write
R/W
PD17072,17073