UPD17073 NEC, UPD17073 Datasheet - Page 70

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

11.2.3 Vector address generator (VAG)
a branch address (vector address) to which the program execution is to be branched.
11.3 Interrupt Stack Register
11.3.1 Configuration and functions of interrupt stack register
the contents of the registers are reset to “0”.
cannot be performed.
(“RETI”) instruction has been executed.
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Caution With the PD17073, the contents of the program status word (PSWORD) are not saved to the stack
When an interrupt request from peripheral hardware has been accepted, the vector address generator generates
The vector addresses corresponding to each interrupt source are listed in Table 11-1.
Figure 11-6 shows the configuration of the interrupt stack register.
The interrupt stack saves the contents of the bank registers when an interrupt has been accepted:
When an interrupt has been accepted, and the contents of bank registers have been saved to the interrupt stack,
The interrupt stack can save up to one level of the contents of the bank registers; therefore, multiplexed interrupt
The contents of the interrupt stack register are restored to the respective system registers when an interrupt return
but retained when an interrupt is accepted. Therefore, the contents of the program status word
must be backed up by software.
Figure 11-6. Configuration of Interrupt Stack Register
Table 11-1. Vector Address of Each Interrupt Source
INT pin
Basic timer 1
Serial interface
Interrupt source
Remark –: Bit not saved
Interrupt stack register (INTSK)
Name
Bit
0H
b
_
3
Bank stack
b
_
Vector address
2
b
_
1
03H
02H
01H
b
0
PD17072,17073