UPD17073 NEC, UPD17073 Datasheet - Page 72

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

11.4 Stack Pointer, Address Stack Register, and Program Counter
exits from an interrupt service routine.
value of the program counter at that time is saved to the address stack register specified by the stack pointer.
the contents of the address stack register specified by the stack pointer are restored to the program counter, and the
value of the stack pointer is incremented by one.
11.5 Interrupt Enable Flip-Flop (INTE)
resets the flip-flop while it is executed.
72
The address stack register saves the return address to which the program execution is to restore when execution
The stack pointer specifies the address of the address stack register.
When an interrupt has been accepted, therefore, the value of the stack pointer is decremented by one, and the
Next, when dedicated instruction “RETI” has been executed after the interrupt service routine has been executed,
Also refer to 3. ADDRESS STACK (ASK).
The interrupt enable flip-flop enables all the interrupts.
When this flip-flop is set, all the interrupts are enabled. When it is reset, all the interrupts are disabled.
This flip-flop is set or reset by dedicated instruction “EI (set)” or “DI (reset)”.
The “EI” instruction sets this flip-flop when the instruction next to it has been executed, while the “DI” instruction
When an interrupt has been accepted, this flip-flop is automatically reset.
This flip-flop is reset on power-ON reset, execution of the clock stop instruction, or CE reset.
PD17072,17073